Chris Shanahan: Toasting beer chemistry

It’s the international year of chemistry, said the brewers’ press release. So I asked Bill Taylor, Lion Nathan head brewer, for one really big thing this means for all of us.

“The major breakthrough, something all brewers work with every day”, said Taylor, “is the understanding of naturally occurring enzymes”.

Since ancient times, Taylor explained, brewers knew that varying temperatures of barley-malt solution (the mash) produced beers of different flavour, alcohol content and body (residual carbohydrates).

But they didn’t understand the mechanism. The discovery of a spectrum of enzymes (many of them similar to those in our saliva) and their sensitivity to temperature finally gave brewers greater control of their craft.

Just as our saliva breaks down starch in bread, different enzymes break down starch in the mash to a range of sugars.

By turning enzymes on or off with temperature, brewers control the level of fermentable sugars, ultimately determining the alcohol level, body and complexity of flavours in a beer.