On 23 October, speakers from the National Collection of Yeast Cultures (NCYC) and Adnams Southwold brewery visited the Forum to talk about ‘The Science Behind Beer’ .
A variety of beers from Adnams was served for tasting alongside the talks, delighting the audience with the insight of how the characteristic flavor and color of each brand was created.
The first speaker, Carmen Nueno-Palop, a microbiologist who studies yeast culture, introduced the role of NCYC in collecting, preserving, and researching various yeast strains.
NCYC, located in the Norwich Research Park, has collected over 530 species and 4000 strains of yeast for a range of purposes from brewing and baking to medical research since its establishment in 1951. Yeast fermentation is central in brewing as it converts sugar to alcohol, carbon dioxide, and other chemical compounds that give beer its characteristic flavour.
Different compounds produced from different strains determine the flavour of beer. For example, diacetyl gives a buttery flavour while acetaldehyde gives a flavour of green apple.
Strain storage is also a vital job of NCYC, helping breweries and other corporations resume work when they lose their yeast strains by flooding or spoilage.
Fergus Fitzgerald, the head brewer of Adnams, gave the next talk on four main ingredients of beer, which are water, barley, hops, and yeast, and how Adnams processes each ingredient.
He passed around different types of malted barley, or malt, and hops, for the audience to smell or taste and emphasised the importance of the mashing stage when malt is combined with hot water and heated.
Different temperatures activate enzymes to break down starches into various types of sugar, creating a diverse flavour. For dry beer, the temperature should be at 65 °C to activate beta amylase, whereas for sweeter beer, the temperature should be over 67 °C to activate alpha amylase.
The broadside, dark beer heated at 70 °C for a sweet flavour. Another ingredient, hop, gives beer a bitter taste and preserves from spoilage.