91av

THANKS to Mark Denny’s entertaining little book on the “science of beer”, I now know that for many years I have taken great delight in drinking yeast excrement. Alcohol, that is. Cheers Mark, I’ll bear that in mind on my next visit to the pub. As Denny points out, alcohol is the waste that yeast cells churn out as they ferment the sugars in grains of malted barley into booze. It is also the biological weapon they have evolved to stop rival bugs stealing their dinner.

Froth! is a nice read, garnished with just the sort of wit I’d expect from a British-born beer aficionado. It will be especially useful to home brewers, as it explains step by step how to make the stuff yourself. Some sections contain too much mathematics for my liking, and I found myself beginning to glaze over with every new equation – partly because I’d taken advantage of Denny’s suggested “intermissions” for beer drinking. But some readers may enjoy the hard sums. Top marks to Denny also for slagging off what he calls “macroswill”, the mass-produced, insipid gnat’s urine that so many pub-goers inexplicably mistake for beer.

Denny pays homage to beer-science guru Charles Bamforth, whose book Beer is now available in its third edition (Oxford University Press, £16.99). More focused on mass-produced rather than home-made beer, this latest version contains new sections informing readers that in ancient Egypt, beer was also used as a mouthwash, an enema and – wait for it – a vaginal douche. New markets for macroswill? Read both books, if you can. Then head down to the pub for a nice cold glass of excrement.