Effect of methanol extract of Vernonia amygdalina on malting and brewing properties of sorghum.
Okoh, I.A., Babalola, G.O. and Ilori, M.O.
The high cost of importing conventional brewing ingredients into some tropical countries where they cannot be produced has led to the adoption of locally available products in their place. In particular, sorghum is now well established as a substitute for barley in countries such as Nigeria, where it is used in both malted and unmalted form. The possibility of using locally available substitutes instead of hops has also been investigated. One possible hop substitute is Vernonia amygdalina, known as "bitter leaf", which is widely grown in Nigeria as a food vegetable, and resembles the hop not only in its bitter flavour but also in its antimicrobial properties. Trials are described in which a methanol extract of bitter leaf was used not only as a hop substitute in the brewing of lager from sorghum malt but also added to the steeping water to control contaminant microorganisms during the malting of sorghum. It was found that bitter leaf extract is more effective at removing bacteria than the formaldehyde solution currently used in many sorghum maltings and does not affect malt quality, but has little or no effect on fungi, which can constitute a serious problem. However, beer brewed using bitter leaf extract as a hop substitute was found to be very similar in composition and flavour to hopped beer brewed from the same sorghum malt.
Keywords : bacteriocide beer bitterness brewing hop substitute malting properties quality sorghum steeping