MBAA Ask the Brewmaster Blog http://www.mbaa.com/brewresources/brewblog/Lists/Posts/AllPosts.aspx RSS feed for MBAA Ask the Brewmaster Blog Tue, 21 May 2013 21:05:24 GMT Microsoft SharePoint Foundation RSS Generator 60 en-US Ask the Brewmaster: Posts http://www.mbaa.com/brewresources/brewblog/_layouts/images/siteIcon.png http://www.mbaa.com/brewresources/brewblog/Lists/Posts/AllPosts.aspx Brewhouse efficiency http://www.mbaa.com/brewresources/brewblog/Lists/Posts/ViewPost.aspx?ID=19 Title: Brewhouse efficiency
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Question

I am reading the brewhouse yield section of "a Handbook of Basic Brewing Calculations" and it states in order to know your brewhouse yield one piece of information needed is your brewhouse efficiency.  In the book it seems to me they guess at an efficiency but how does one calculate this number?

Answer

There are several efficiency calculations that are good to know from your brewhouse and every operation will be different depending on the process and materials used.  However the calculations for everyone are basically the same.  Let’s start with your mash yield which is a measurement of how much of the available starch you are converting and extracting from your mashing/lautering process per the amount of material used. 

Mash yield = Lbs of extract collected/lbs of malt (or other material) used. 

 
To get lbs of extract you need to accurately measure the volume of wort collected in your brewkettle (remember to multiply this number by 0.96 to account for thermal expansion) and the degrees Plato.  You can get the lbs extract/bbl from extract tables (MBAA Practical Handbook for the Specialty Brewer Table 5.2) or using the equation:
 
[(259 + deg P)deg P]/100
Normally the mash yields will be about 65% for malt, 75% for corn grits and 82% for syrups. This is a useful ratio used to calculate recipe grist weights.
 
Brewhouse efficiency is simply a ratio of what is recovered vs what was put in:   Lbs of extract collected divided by lbs of extract potential from the grist.  Although this efficiency ratio can be used at any step in the process, ie lauter to kettle, kettle to whirlpool tank, etc, ultimately brewhouse efficiency uses this ratio of outputs to inputs to measure just how efficiently the brewhouse has used the malt and other materials to produce a given volume of wort at a particular Original Extract (OE).  The higher the number, the less waste and loss.
 
To determine your brewhouse efficiency you will need to know how much extract is in each ingredient in the grist.  The malt house will supply a Certificate of Analysis and on the COA are numbers for % extract.  The listed extracts will normally include a “Fine Grind dry basis” which is the ultimate available amount of extract in complete extraction and does not include the weight of moisture.  The more practical “Coarse Extract as is” (moisture included) will give you a more realistic limit of how much your brewhouse could yield from the malt and is the number to use when making efficiency calculations.
 
The brewhouse efficiency then will be a ratio between what you could possibly expect to yield and what you actually yield.  To determine efficiency first multiply the coarse grind as is extract % by the weight of the grist  for each component, ie lbs pale male x X% coarse extract to get lbs extract possible from pale malt, same with crystal malt, wheat malt, etc. Total up the weight from each and this will give you total lbs of extract potential in the grist.
 
Your final yield from the brewhouse can be defined as the amount of extract actually recovered as cold wort in the fermenter compared to what you started with in the mash tun.  To get that number you will accurately measure the volume of cooled wort collected in the FV tank and its gravity in degrees Plato.  From the extract tables or extract equation determine the lbs of extract/bbl.  Multiply the lbs extract/bbl by the bbls of wort collected to get lbs of extract in the FV.  This is your realized lbs of extract from the grist.
 
Total up the lbs of potential extract from your grist and then divide into the lbs of extract collected in your fermenter and this will give you the brewhouse efficiency.  You can use this same ratio at each step in the brewhouse process to determine efficiencies and find sources of losses.  Brewhouse efficiencies of 90-93% for single infusion mash tuns are possible with a good mill, grind control and good lautering practices as well as minimal losses through to the FV tank.  Automated brewhouses with a lauter tun or mash filter will see brewhouse efficiencies of 96-98%.

Published: 4/15/2013 5:07 PM
]]> Karl Ockert Calculations Mon, 15 Apr 2013 22:10:42 GMT http://www.mbaa.com/brewresources/brewblog/Lists/Posts/ViewPost.aspx?ID=19 Bottle conditioning http://www.mbaa.com/brewresources/brewblog/Lists/Posts/ViewPost.aspx?ID=18 Title: Bottle conditioning
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Question

What is the best process and technique for introducing wort and yeast back into a beer just prior to packaging? The goal is to bottle condition the ale using wort that is produced in our brewhouse and yeast we pull from our FV cones.  I am concerned about hygiene and sterility of the transfer vessel, as well as of the final product.  Perhaps injecting pasteurized wort?  If we take the wort from our brew house post heat exchanger into a sterile vessel (keg), and then stored it in a cold box/refer, how long do you think that wort would be good for?

Answer

I worked with bottle conditioning for about 15 years (BridgePort IPA), and my first quesiton back to you is why do you want to use wort?  In my experience wort for bottle conditioning has problems with inconsistency, contamination and trub solids carryover.  Wort that is not used fresh but kept refrigerated is prone to contamination and flavor issues.  Use of dextrose sugar on the other hand will give you consistent, predictable control over fermentability, sterility and there is no trub or other solids that will carry through.  A good place to start experimenting with dextrose additions is about 1 lb per bbl.  To prepare the sugar solution and yeast inoculation:

  • Dissolve the sugar in a few gallons of water and heat to a minimum of 180 deg F for a minimum of 20 minutes
  • Pump the hot sugar solution into the bright beer tank
  • Pump beer into the tank
  • During the tank transfer, inject yeast slurry to achieve 1 million cells/ml at tank full
  • Check tank gravity and cell count to confirm
  • Mixing the sugar solution and yeast into the beer can be done by pump recirculation or agitator and should be done through the packaging of the beer
 
You might find that for bottling it’s a good idea to carbonate slightly to achieve fobbing prior to crowning.  Test your results by taking daily carbonation and gravity measurements over 14 days.

Published: 4/4/2013 6:12 PM
]]> Karl Ockert Packaging Thu, 04 Apr 2013 23:14:56 GMT http://www.mbaa.com/brewresources/brewblog/Lists/Posts/ViewPost.aspx?ID=18 Hydrometers http://www.mbaa.com/brewresources/brewblog/Lists/Posts/ViewPost.aspx?ID=17 Title: Hydrometers
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Question

I am a young brewer and have been wondering for some time about gravity of my lauter.  It is common knowledge that you stop collecting wort into the boil kettle when the gravity reads below 1.008 – 1.010.  However is this gravity being corrected for its elevated temperature or do you take it “as is”?  In other words, if I take a sample of wort toward the end of my lautering process and it reads 1.002 at 160 degrees Fahrenheit,  is this the point to stop?  Or do I correct for temperature which results in an actual gravity of 1.024.  To be safe I have stopped lautering when I fall below the specified range, but my efficiency takes a bit of a hit.  Just wondering if maybe I am being to careful.

Answer

It’s pretty well documented that you should stop lauter running’s at 2 deg Plato (SG 1.008) to avoid absorbing astringent tannins from the grain into the wort.  Your hydrometer is calibrated to read at a certain temperature which should be stamped or labeled on the stem, usually 60 deg F or 68 deg F, that is the temperature where the reading will be accurate.  The hydrometer measurement is based on the density of the wort, the warmer the liquid the less dense it is so it will read lower at a warm temperature than it will at a cooler temperature.  If you are reading the hydrometer at 160 deg F you are reading it at a very low density and it will give you an inaccurately low reading.  In your example you are taking a measurement at 160 deg F and getting a reading of SG 1.002 (0.5 deg Plato) with a  corrected reading of SG 1.024 (6 deg Plato), the latter is the accurate reading and you should continue to run off until you get a corrected reading of 2-2.5 deg Plato (SG 1.008-1.010).  The reason why you are losing efficiency in extracting from the mash is because you are cutting your run-off too early. 

To cool the sample quickly in the brewhouse you can use a small stainless cup for the sample sitting in a water bath with cold water running through or ice.  Stir the wort sample in the cup with a bi-metal or digital thermometer (never mercury!!) until the desire temperature is reached then take your hydrometer measurement.  Invest in a good quality calibrated hydrometer with temperature compensation to get the most accurate results, these are available through commercial brewing supply or laboratory supply websites.  The most accurate will come in concise ranges, ie 0-12 deg Plato and 9-21 deg Plato.

Published: 4/3/2013 5:02 PM
]]> Karl Ockert Measurements Wed, 03 Apr 2013 22:04:40 GMT http://www.mbaa.com/brewresources/brewblog/Lists/Posts/ViewPost.aspx?ID=17 Problems with foamy nitro beers http://www.mbaa.com/brewresources/brewblog/Lists/Posts/ViewPost.aspx?ID=16 Title: Problems with foamy nitro beers
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​Question

We are having problems with foaming in our nitro beer, we carbonate it to a low level and then use a blended gas to push it through the nitro tap. 

Answer

The thing that makes nitro beers give that wonderful “break out” of tiny bubbles and produce the creamy, stable head of foam is that unlike CO2, nitrogen does not dissolve well into beer but once dissolved it likes to stay there, in fact the nitro tap system forces the beer under high pressure through an “agitator plate” containing small holes in order to rouse the nitrogen to start its foaming process.  In the world of physics and gas laws substances try to come back into equilibrium with their atmospheric concentration and the atmosphere we are breathing right now is about 78% nitrogen, 21% oxygen and about 0.04% CO2.   That means that once nitrogen has been dissolved into the beer under high pressure it wants to stay in solution and forms those tiny bubbles which have a high surface tension and are wonderfully stable at the top of the pint.  Essentially a stable nitrogen beer is interrupted by large amounts of carbonation present, which unlike nitrogen, wants to come out of solution fairly readily (there being a much smaller concentration of CO2 in the atmosphere).  CO2 present in large amounts in the beer under the high driving pressure of a nitro tap will yield foam.  To produce nitrogenated beers you need to eliminate carbonation- CO2 is not your friend- that means:
  • Only Nitrogenate beer in a tank that is ASME rated for 2 bars (30 psig) or more and fitted with overpressure relief
  • Nitrogenate in the bright tank with pure Nitrogen gas (only- no CO2 blends) under high pressure, 25 psi plus and at cold temperature (0C)
  • Use pure Nitrogen gas in purging and pressurizing the keg, instead of CO2 or blends, at only a slightly lower pressure than the drive pressure from the bright tank
  • Use pure Nitrogen to counter pressure the bright tank while kegging

  • Nitrogen taps can use a “Guinness blend” of about 25% CO2 and 75% Nitrogen, this will allow a very small amount of carbonation to develop and assist the nitrogen breakout.

Published: 4/3/2013 4:10 PM
]]> Karl Ockert Nitro beers Wed, 03 Apr 2013 21:15:08 GMT http://www.mbaa.com/brewresources/brewblog/Lists/Posts/ViewPost.aspx?ID=16 Brew kettle surface area calculations http://www.mbaa.com/brewresources/brewblog/Lists/Posts/ViewPost.aspx?ID=14 Title: Brew kettle surface area calculations
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​Question:

We are building a new kettle and want to heat it with steam. Our boiler will provide plenty of steam (1200lb boiler) and the batch size 25HL.

We are trying to find the surface area required to bring the kettle to the boil in 30min.

The kettle will have an agitator to move the wort in the kettle.

Can you point me in the right direction to find this info please?  

Answer:

I had to make a few assumptions to answer your question, and pardon me for using imperial units.  Your boiler at 1200 lbs of steam per hour looks adequate, I calculate a need for 510 lbs/hour of dry steam to pre-heat to boiling and approximately 375 lbs of steam per hour to maintain the kettle boil. 
 
25 hL cold wort = 21.3 US bbls and assuming you are evaporating 5%/hr with a one hour boil time your total wort collection should be 22.4 bbls
 
Assuming a 12P wort the SG is 1.048
 
Heat load= 5/100 x 22.4 bbls x 258.5 lbs water/bbl x 1.048 x 970.6 BTU/Hr/ lb water = 294,500 BTU/hour
 
Surface area of heating required assuming 45 psig dry steam (292F from steam table):
 
Heat Load= UA(T1-T2)
Where U for boiling wort is 220 BTUs/Hr/SqFt/DegF
A is the square feet of surface area needed
T1 = temperature of 45 psig steam
T2= boiling temperature
 
So with the givens we can solve for A:
 
A= 294,500/220-(292-212)= 16.7 SF
Taking into consideration a 5% factor for radiant heat loss, make the SF equal 17.6 SF (1.64 Square Meters)
 
You should check these assumed figures against your actual values ie wort deg P, desired evaporation rate, steam pressure, etc and with your fabricator as well to determine an adequate surface area for your kettle.  Depending on the heating format you are using you can turn on bottom dimple jackets while collecting wort to achieve boil by the time the wort collection is completed.
Published: 2/27/2013 2:03 PM
]]> Karl Ockert Brewhouse Equipment Wed, 27 Feb 2013 20:06:29 GMT http://www.mbaa.com/brewresources/brewblog/Lists/Posts/ViewPost.aspx?ID=14 Sugar additions to boost ABV http://www.mbaa.com/brewresources/brewblog/Lists/Posts/ViewPost.aspx?ID=15 Title: Sugar additions to boost ABV
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​Question:

I’m reading on the crabtree and chaptalization. I have been adding raw sugar to fermented beer in my brewery for many years with great results, but really instable result. I started to look at the crabtree effect as an explanation, but both subject are greatly unexplained on the internet which makes it difficult to understand. Do you have any reading to suggest or some experience you had with adding raw sugar or any opinion of what are the underlying mechanism that occurs in the crabtree effect and chaptalization? From what I understand both are opposite, but both occurs, without anyone knowing at what range.

Answer:

The “crabtree effect” has to do with the yeast’s inability to produce respiratory enzymes in high concentration sugar solutions even when oxygen is present.  So if you are adding sugar to a working fermentation and it picks up air it will still “aerobically ferment” the sugar and produce ethanol.  This is why when growing baker’s yeast they avoid alcohol production by keeping the sugar concentrations low and fed in a controlled manner along with aeration.   Chaptalization is the addition of sugar to boost the initial gravity at the start of fermentation or during fermentation.  This practice is used by winemakers on musts that are not high enough in Brix to get the alcohol concentration they are looking for and also by brewers who want to build up the fermentable extract of their starting wort to make very high alcohol beers.  The sugars used for chaptalization can be anything that is fermentable, ie. Sucrose, Belgian candi-sugar (sucrose), glucose, high fructose corn syrup, molasses, honey, etc and the sugars can be fed into the fermentation as it proceeds without additional aeration.  As sugar concentrations increases the yeast may start to produce interesting flavor compounds like fruity esters and solventy higher alcohols, this will be affected by the temperature of the fermentation, the concentrations of the sugars added and the yeast itself.

I asked Chris Boulton of Univ of Nottingham and yeast expert about your question and here is his more detailed response:

Regarding your question I would not disagree with anything you have said.  There are two Crabtree effects (long and short term).  The former seems to operate at the enzyme level such that at high sugar concentrations the respective Km values for the pyruvate dehydrogenase and pyruvate decarboxylase are such that the majority of the carbon flow goes to acetaldehyde (and ethanol) and not acetyl-CoA.  The longer term effect has the same gross effect but it operates via repression of the genes involving carbon flow through pyruvate dehydrogenase part of the TCA cycle and the respiratory electron transport chain.  These effects have the same gross outputs and as you say are independent of oxygen and reflect the fact that with a surplus of sugar the yeast can generate more than enough ATP via glycolysis to satisfy its energy requirements.  The result though is that you get a lot less biomass formed so as you also say the fed-batch fermentations make sure this doesn't happen by feeding in the sugar at an exponential rate balanced with growth rate and they supply a lot of oxygen.  This results in a massive increase in biomass yield.  As an approach to increase abv in brewing fermentations feeding sugar in batches avoids the possibility of arrest of fermentation via osmotic shock.  The sugars are taken up in order so if you feed with sucrose or glucose this will delay the uptake of maltose.  If you feed a more complex sugar source (plus other nutrients) this will have differing effects.  The flavour changes probably reflect the fact that the added sugar changes the C:N ratio (and C to other nutrients as well).  The effect is to change the concentrations and spectrum of precursors to pathways such as those leading to higher alcohols.

Essentially if you are adding sugar the fermentation do this in a steady feed as the fermentation is proceeding.

Published: 3/6/2013 12:16 PM
]]> Karl Ockert Yeast Wed, 06 Mar 2013 18:19:53 GMT http://www.mbaa.com/brewresources/brewblog/Lists/Posts/ViewPost.aspx?ID=15 (1) Fermentation Vessels Shape and (2) Oxygen During Tank Transfers http://www.mbaa.com/brewresources/brewblog/Lists/Posts/ViewPost.aspx?ID=13 Title: (1) Fermentation Vessels Shape and (2) Oxygen During Tank Transfers
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Question

​I've been looking and asking around for insight into a couple of issues we're encountering in our multi-location brewpub operation:

1) how does fermentation vessel shape/design impact fermentation rate/degree of attenuation? We've noticed significant differences between the times when we completely fill our 20 bbl unitanks and when we only fill them half way with 10 bbl. batches (faster/further attenuation during 1/2 fills).

2) is there a safe, effective, and efficient way to ensure minimum oxygen uptake during transfers between tank? I understand the theory of filling a tank with water and pushing water out with co2, but that is not terribly practical for many small breweries w/o dumping most of the water. I've heard about meters that measure outflow of gas from tanks during purging (http://www.analox.net/product-docs/manual-20.pdf / they measure in o2% down to 0.1%), but have not come across any info that points in a definitive direction based on quantifiable measurements of o2 pickup between tanks. Sniffing the tube at the end of the CIP arm is often employed, but does not seem terribly safe or verifiable between users' sniffers.

Answer

1) There are several factors affecting fermentations that you are describing:

  • Geometry of the FV tank affects fermentation and flavor. Very tall tanks suffer from CO2 scrubbing of aroma compounds during active feremntation, some larger breweries blend beer made from tall CCV’s with beer made from smaller tanks in order to retain these aromatic properties. 
  • Rate of fermentation in single brew vs multi brew fermentations can be affected somewhat by tank geometry but will have more to do with the fact that the single brew will have full aeration and yeast pitch to start fermentation without the addition of sugars from added brews which will temporarily slow the fermentation down and may even cause stratification in multi brew fermentations. 
  • The attenuation rate is controlled in the brewhouse by the grist composition, mash temperature, rest time, etc. and not the geometry of the tank or the number of brews added unless there is incomplete aeration, pitch rate or some other fermentation problem. An easy bench top test to find out where the fermentation should stop is a forced attenuation test. Take 500 mls of oxygenated wort during wort cooling into a 1 liter flask, pitch with 50 mls of your yeast and set on a bench at room temperature, 68F (20C) with a cotton top, rouse this regularly or better yet use a stir bar to keep it continuously stirring. The wort should attenuate fully in 24- 36 hours and let you know the “attenuation limit” of that batch of beer to compare with your FV results.

2) The best way to de-aerate a tank is the water push method you mentioned but this does waste water unless it can be captured and used for something else like tank rinsing. To de-aerate small vertical beer tanks, ie 5-100 bbls its pretty easy to gas them with CO2, this can be done by adding CO2 gas at a slow rate through the bottom valve tank inlet after sanitizing for about 10-15 minutes and letting the gas exit through the vent line, preferably out of the building. Although this is not as efficient a way to de-aerate the tank as the water push and will not completely eliminate the oxygen present, it will substantially reduce the oxygen level for your transfer and is certainly better than leaving it with an normal atmospheric environment. 

!!CO2 WARNING: Serious Care must be taken that the room in which you gas a tank has excellent ventilation as CO2 gas accumulation can cause asphyxiation! Vent the tank out of the building while gassing with CO2!!

Gassing the tank should provide enough reduction of oxygen for a safe tank transfer. Some other factors to consider for low oxygen pick up:

  • Pack the hoses, pumps and lines with water and then push the water out with beer at a tee located at the tank inlet at the start of the transfer. This will reduce oxygen pick up from the empty transfer line/hose.
  • Pump the beer slowly at first to build  a level that will cover the inlet and avoid “fountaining” the beer in the tank
  • CO2 “dusting” or addition of a small amount of CO2 gas through a carbonating apparatus can help flush out oxygen, especially post filter. The dusting though can also flush out beer aromatics like hop aroma so use only a minimal amount.
  • Gas the tank again post transfer to push out any air in the tank head space and bung it closed under a slight positive pressure.

Published: 2/15/2013 12:07 PM
]]> Lauren Bennett Brewhouse Equipment Fri, 15 Feb 2013 18:11:54 GMT http://www.mbaa.com/brewresources/brewblog/Lists/Posts/ViewPost.aspx?ID=13 Ammonia or Freon/Halocarbon Equipment http://www.mbaa.com/brewresources/brewblog/Lists/Posts/ViewPost.aspx?ID=12 Title: Ammonia or Freon/Halocarbon Equipment
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Question

​We have heard that large breweries use ammonia refrigerant as part of their brewing process, but what is used in smaller systems, and what defines small? Could you point me in the right direction to understand the equipment/refrigerant and brewing capacity parameters.

Answer

Thanks for writing with your question regarding refrigeration use in breweries. All brewers use some form of refrigeration systems in the brewing and fermentation processes. Direct ammonia chilling is still used by a few older plants but has largely been replaced with a glycol interface. Typically Freon type or ammonia based systems are used to chill a 30% glycol solution to about 25 deg F (-4C) which is circulated through a distribution system that can send cooling to tank jackets, coils and heat exchangers throughout the plant.  The amount, sizing and types of system used depends largely on the size and capacity of the brewery plant.  Small brewpubs may require fairly simple 10-20 hp Freon based glycol chillers, larger craft breweries may use multiple units of 50 hp reciprocating ammonia to glycol chillers and of course larger breweries will use much larger and more elaborate systems. For more information I would point you to your local MBAA district Cincinnati where you can attend a meeting and meet brewers from your area including those from the MillerCoors plant in Trenton, AB in Columbus and Boston Beer in Cincinnati as well as smaller regional and brewpub brewers.  More information about District Cincinnati.  

Published: 2/15/2013 11:58 AM
]]> Lauren Bennett Brewhouse Equipment Fri, 15 Feb 2013 18:06:17 GMT http://www.mbaa.com/brewresources/brewblog/Lists/Posts/ViewPost.aspx?ID=12 Adding Lactic Acid to the Mash http://www.mbaa.com/brewresources/brewblog/Lists/Posts/ViewPost.aspx?ID=11 Title: Adding Lactic Acid to the Mash
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Question

I read in Fix (1997) that lactic acid will influence the pH of the brewing water and giving Calcium lactate as a result. Does this stays in the product after brewing? I’m looking at this scenario because I get at the end of fermentation, a good attenuation with a great flocculation of the yeast, but the beer stays really hazy and I have a lot of difficulty filtering it. I do step mash at 50 Celsius for protein rest, but still get some problems. I thought it could be chill haze, but everyone told me that a rest at 50 Celsius would help, and I can see that it doesn’t. Do you have any advice?
 

Answer

The addition of lactic acid to the mash will help reduce the pH of the mash which assists with several aspects of good wort production:

  • Lower pH helps the diastatic enzyme action in converting starch to sugars
  • It helps reduce the amounts of astringent tannins extracted from the husk

Typically the mash starting pH should be about 5.8 and the conversion pH about 5.4-5.5. Addition of calcium either with gypsum or calcium chloride at 100-200 ppm will normally produce a mash within these pH ranges. However you can also adjust the pH downwards by adding small amounts of lactic acid either food grade, naturally produced by lactic bacteria or using sauer malt in your grist. A proper lactic acid addition should not have much, if any, effect on haze in the beer or filtration problems. For haze and filtration problems I would suggest you investigate:

  • Malt quality, particularly high protein levels and beta glucan above 100 ppm
  • Calcium additions to mash and brew kettle
  • Kettle finings efficiency
  • Trub formation/separation and proper wort clarity prior to cooling
  • Yeast settling, non-flocculent yeasts may require use of a fining agent prior to filtration
  • Chill haze finings with hydro siica agents prior to filtration
Published: 2/15/2013 11:54 AM
]]> Lauren Bennett Water Fri, 15 Feb 2013 17:57:59 GMT http://www.mbaa.com/brewresources/brewblog/Lists/Posts/ViewPost.aspx?ID=11 Yeast-to-Brew Ratio (in homebrewing) http://www.mbaa.com/brewresources/brewblog/Lists/Posts/ViewPost.aspx?ID=10 Title: Yeast-to-Brew Ratio (in homebrewing)
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​Question

I'm a new home brewer and have made my first batch from a straight 'out-of-the-box' mix from the local brew store. I'm trying another recipe, this one found out of Charlie Papazian's book and there's no indication as to how much yeast to use for the recipe. What do you recommend as a general ratio for 'yeast to brew'?  Also, if I were to try a yeast starter, do you have recommendations of ratios in that sense?
 

Answer

Thanks for writing with your question and congratulations on your start in brewing! In regards to yeast ratios brewers use a rule of thumb that you should pitch one million cells per ml per degree Plato (% sugar by wt) in your starting wort. For instance if your wort has a starting gravity of 1.048 you can divide that by 4 to get approximately 12 deg Plato and you would pitch 12 million cells per ml into the cooled brew.  For home brewers this level of precision is not really necessary, most homebrew recipes of five gallons (19-20 liters) can be pitched with one packet of active dried brewing yeast or a single live yeast "smack pack". For best results follow the instructions given on the packages but remember to cool the wort to at least 68F (20C) and since yeast initially needs oxygen to grow and reproduce try to aerate your cooled brew either by agitating with a large wisk or spoon or better yet bubbling air through with something like an aquarium pump. The important thing as you continue to brew and experiment is to keep a journal and write down what you have done and the results you got so that you can fine tune your brewing and the quality of your beers. I suggest you also try joining your local homebrew club and talking to others about their experiences and techniques, brewing is a very sociable community and people who brew love to share stories. Happy brewing!

Published: 2/15/2013 11:51 AM
]]> Lauren Bennett Homebrewing; Measurements; Yeast Fri, 15 Feb 2013 17:54:20 GMT http://www.mbaa.com/brewresources/brewblog/Lists/Posts/ViewPost.aspx?ID=10 Whirpool Placement http://www.mbaa.com/brewresources/brewblog/Lists/Posts/ViewPost.aspx?ID=9 Title: Whirpool Placement
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​Question

We are having a whirlpool built and are having a little disagreement on the tangential inlet port.

Here's the deal. we can put it anywhere on the tank or we can put multiple inlet ports. What I need to know is, should we put it: Low as possible to reduce the splashing as it enters the tank?  mid to higher to ensure proper spinning speed. Or two ports, one low and one higher so that you can switch up as the tank fills? 

We'd like to maximize our time, get proper separation, and not be too hard on the wort.

The most recent plan is to have the WP inlet about a 1/3 liquid level up the tank.  

Any opinions or facts you can give on the inlet issue or any other common problems/solutions that you know of would be great. 

Answer

As for whirlpools, the standard geometry is 1:1 height to diameter and the level of the inlet is usually set at 1/3 wort volume.  You want to make sure the wort speed is about 15-20 feet per second by adjusting the diameter of the inlet nozzle depending on the GPM of your pump.  Velocity = (0.408 x GPM)/pipe ID^2.  That way you will get best trub pile formation and settling.  Avoid having any thermo probes or other things sticking into the tank.  Multiple draws are good to avoid having to wait all that long before cooling, you can position them at ¾ height, ½, ¼ and then at the very bottom with a large sump drain to avoid cavatating as you get the last drops.

Published: 2/15/2013 11:50 AM
]]> Lauren Bennett Brewhouse Equipment Fri, 15 Feb 2013 17:51:48 GMT http://www.mbaa.com/brewresources/brewblog/Lists/Posts/ViewPost.aspx?ID=9 Cellaring/Serving Tank Purging http://www.mbaa.com/brewresources/brewblog/Lists/Posts/ViewPost.aspx?ID=2 Title: Cellaring/Serving Tank Purging
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​Question

We've been looking for some information on 'best practices' for preparing brew pub conditioning and serving tanks (7, 10, and 20 bbls) for receiving beer. This question is motivated by our experience of premature spoilage of our Stout and Brown ales (accelerated oxidation in melanoidin-rich environment?). I've been digging around on the BA Forum and in the MBAA Practical Handbook, but have not found anything specifically addressing how best to purge a tank with CO2.

I have had decent results over the years using the "sniff test" method of introducing CO2 through the bottom of our conditioning and serving tanks and gauging when CO2 displaces O2 by the 'sting' of the discharging gas in the nose. In spite of the subjective nature of that method, it has proven a decent, if unsafe, SOP. Now that we have three pubs staffed by three different brewers, the method is breaking down.

Are there any resources you know of that address 1) efficacy of purging from the bottom w/ CO2 and transferring fully-attenuated beer immediately/on the same day vs. letting "purged" tank stand overnight under pressure before transferring; and 2) a device that can accurately, consistently, and reliably detect gaseous O2 levels as they exit a conditioning/serving tank (in our case through the CIP arm)? Questions have arisen about to what degree o2 and CO2 mingle when purging a tank and how that might impact the life expectancy of our Brown and Stout. No doubt there are other avenues of inquiry about why beers might spoil, but we're only currently experiencing this in these two styles (and not right away upon serving = ~3 weeks after brewing).

FYI: similar methods are employed prior to moving/serving hop-centric pale ales, and we're not experiencing the same degree and/or rate of degradation.

Any insights you might be able to share would be much appreciated.

Answer

The best way to purge a tank is to fill it to overflowing with water and then press the water out with CO2 or N2 gas. The water can be pressed to another tank for other use or sent to the drain.  This will give you an anaerobic interior to the tank but the beer going in should be through a packed line. Fill your beer hoses with water until you get all the air bubbles out and then push the water out with beer before allowing it to go into the tank that way you don’t re-contaminate the tank with air.

Published: 2/15/2013 11:04 AM
]]> Lauren Bennett Brewhouse Equipment Fri, 15 Feb 2013 17:26:34 GMT http://www.mbaa.com/brewresources/brewblog/Lists/Posts/ViewPost.aspx?ID=2 Purging Kegs with Nitrogen vs CO2 http://www.mbaa.com/brewresources/brewblog/Lists/Posts/ViewPost.aspx?ID=3 Title: Purging Kegs with Nitrogen vs CO2
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​Question

I was hoping you could possibly provide some input on this situation for me. We are currently expanding our “nitro” production by installing a 150bbl 25psi pressure rated vessel, along with the vessel expansion we are discussing a bulk nitrogen setup. If we do go with a bulk setup it was suggested that we begin purging our nitro ale kegs with nitrogen instead of CO2 (we currently purge with CO2 and have seen no ill affects) I replied to this by suggesting that we purge all kegs with nitrogen as it tends to be cheaper than CO2. what are your thoughts on this?

Answer

It is better to purge nitro kegs with nitrogen as CO2 is the enemy of good nitrogenation and some of the CO2 will dissolve in the beer as it fills, you really want to limit CO2 in nitro beers.  The opposite is true for a carbonated beer, which will lose CO2 as it fills in a nitrogen environment and flatten out (it will not dissolve much N2).

Published: 2/15/2013 11:27 AM
]]> Lauren Bennett Brewhouse Equipment Fri, 15 Feb 2013 17:29:08 GMT http://www.mbaa.com/brewresources/brewblog/Lists/Posts/ViewPost.aspx?ID=3 Using VDK Levels to Determine when Fermentation is Complete http://www.mbaa.com/brewresources/brewblog/Lists/Posts/ViewPost.aspx?ID=8 Title: Using VDK Levels to Determine when Fermentation is Complete
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​Question

I have a question about using VDK levels to determine when fermentation is complete and the beer is ready to be filtered. We talked about this briefly in the Brewing and Malting course and I was wondering how this is commonly done. I've found a method for testing VDK using a spectrophotometer in the ASBC methods cd. I was wondering if the common method is to test VDK levels and release the beer for filtration after the levels are below flavor threshold? Or is it common to also test for VDK precursors like alpha-Acetolactate to determine that VDK levels will not increase? Thank you for your time and any help on clearing this up.

Answer

The ASBC spec method is not all that reliable although may be good enough to give you some baseline measurements, you could also correlate this to a GC by sending out duplicate samples to an outside lab. It is difficult to test for acetolactate as it easily oxidizes into diacetyl. If diactyl is above 0.1 ppm most people will taste it. In most warm, ale making breweries the yeast will mop up the diacetyl by reducing it to 2,3 butanediol which has no noticeable flavor. In my old brewery we usually yielded about 0.04 ppm diacetyl or less and not even the most sensitive diacetyl taster (me) could pick it out. 
 
A quick easy method for checking a sample by taste is to warm your sample in a 150F water bath for 30 minutes. Then cool down and taste. This quickly converts precursor and brings out the diacetyl character that has potential to develop. I hope this helps answer your question but let me know if you have any others.

Published: 2/15/2013 11:42 AM
]]> Lauren Bennett Measurements Fri, 15 Feb 2013 17:44:52 GMT http://www.mbaa.com/brewresources/brewblog/Lists/Posts/ViewPost.aspx?ID=8 Yeast Brinks http://www.mbaa.com/brewresources/brewblog/Lists/Posts/ViewPost.aspx?ID=7 Title: Yeast Brinks
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Question

​I have two main questions. The first is how do you use a yeast brink? I realize that that is a bit of an open question, but I am really unclear on how they are used in the real world.  Do you use load cells or do you rely on some sort of electronic feedback like a turbidity meter?  My second question is, can you describe a back-of-the-envelope calculation for determining the size needed?

Answer

Yeast brinks are pretty commonly used to hold yeast in suspension at a temp of about 2C, they are usually fitted with a sanitary, cleanable stirring agitator or sometimes they are used with a recirculation pump system.
 
The brinks I am familiar with use a stirring agitator fitted from a top plate on the top of the tank.  The agitator top plate also has CIP inlets, and safety valving for over and under pressure. Alfa Laval sells these among others. We used load cells on the brinks and added a calculated weight of yeast slurry to each brew based on cell count in the slurry and target cell count in the wort. We would enter the weight onto a controller and a CO2 valve would open to push the yeast out into the wort stream through an automatic valve. This worked very well and could be done manually as well.
 
In regards to sizing, you usually yield about 3-4 times that amount of yeast per fermentation that you put in. I would consider sizing at 1.5 times your normal pitch rate. Make sure it has a jacketed cone and sides for maximum cooling capacity and a temp well inside the cone (pointed up). Hope this helps, let me know if you have any other questions.  I would also encourage you to attend your next district MBAA meeting if possible and use the opportunity to discuss this issue with other brewers who could add their insights.

Published: 2/15/2013 11:34 AM
]]> Lauren Bennett Brewhouse Equipment; Yeast Fri, 15 Feb 2013 17:41:29 GMT http://www.mbaa.com/brewresources/brewblog/Lists/Posts/ViewPost.aspx?ID=7 Brewing in a Copper Kettle http://www.mbaa.com/brewresources/brewblog/Lists/Posts/ViewPost.aspx?ID=6 Title: Brewing in a Copper Kettle
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Question

​Is brewing in a copper kettle safe?

Answer

Brewers have used copper kettles for a long time so as long as the kettle is clean, rinsed and does not have any lead seams it should be safe.

Published: 2/15/2013 11:33 AM
]]> Lauren Bennett Brewhouse Equipment Fri, 15 Feb 2013 17:34:18 GMT http://www.mbaa.com/brewresources/brewblog/Lists/Posts/ViewPost.aspx?ID=6 Measuring Alcohol http://www.mbaa.com/brewresources/brewblog/Lists/Posts/ViewPost.aspx?ID=5 Title: Measuring Alcohol
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​Question

I'm a home brewer and I'm trying to figure out the most accurate way to measure alcohol.  Is a hydrometer or refractometer more accurate?  If I use a refractometer, how do I convert that to the actual alcohol percentage?

Answer

A refractometer will only measure sugar accurately, once you beer ferments you need to use a hydrometer.  Best to get a as good a hydrometer as you can, preferably one with temperature adjustments.  For the easiest way to get a close estimate of alcohol content you need to convert your Original Gravity and Final Gravity to Degrees Plato, this is easily done just divide the last two digits by 4, for example 1.048 is 12 Degrees Plato.  Once you have these two numbers converted you can estimate alcohol as % by weight :

(Original Gravity – Final Gravity) x 0.46

You can convert % ABW to Alcohol by Volume by dividing ABW by 0.789. 

That’s your beer math lesson for today, hope it helps your brewing!

Published: 2/15/2013 11:31 AM
]]> Lauren Bennett Measurements; Homebrewing Fri, 15 Feb 2013 17:32:38 GMT http://www.mbaa.com/brewresources/brewblog/Lists/Posts/ViewPost.aspx?ID=5 Beer Definitions http://www.mbaa.com/brewresources/brewblog/Lists/Posts/ViewPost.aspx?ID=4 Title: Beer Definitions
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​Question

Is there any Code or Regulatory document where the different types of beer are defined? I am interested in if malt and adjunct use is defined or regulated by variety.

Answer

Yes you can go to the TTB website, http://www.ttb.gov/beer/index.shtml and have a look around there are various labeling guides and definitions.

Published: 2/15/2013 11:29 AM
]]> Lauren Bennett Definitions and Regulatory Information Fri, 15 Feb 2013 17:30:21 GMT http://www.mbaa.com/brewresources/brewblog/Lists/Posts/ViewPost.aspx?ID=4