The Others is a monthly series looking at the people who aren’t brewers that help to produce beer and get it onto your tastebuds. This month, the people who look after the yeast…
Yeast is arguably the underrated ingredient in beer. As a community, the beer drinking world raves about the many various hops that impart their wondrous aromas and flavours, yet when it comes to yeast, aside from the sour beers of Belgium, not much is said about them.
This is probably because many drinkers don’t even realise that yeast imparts more than just alcohol into a beer. Certainly for myself, it is something that I have come to discover relatively recently, and I see no reason why a casual beer drinker would even think about what flavours the yeast is adding.
Geuze Boon is one of the many Lambic beers to come from Belgium
Arguably, the most obvious effect on a beers taste from yeast can be seen in the many sour beers, including the Lambics and Flemish Reds from Belgium. The Lambic style is produced using Spontaneous Fermentation, which involves allowing the airborne yeast to ferment the beer. The yeast is unique to the area in which the lambic beers are brewed, and as a result, Lambics are a style produced exclusively in Belgium.
Some brewers in other countries brew sour beers using strains of the yeast found in the Lambic breweries, the most common being Brettanomyces bruxellensis. These will be made using more controlled fermentation methods to avoid contamination with airborne yeast which may impart unwanted flavours.
The yeast used in many wheat beers contributes a banana flavour to the taste. This is also present in Brakspear’s Triple. The yeast used by Fuller’s Brewery has, for some (I’ve yet to recognise it myself), a marmalade characteristic, that is present throughout the brewery’s range of beers.
Last year I asked Chris Bond, collection manager at the National Collection of Yeast Cultures in Norfolk, some questions about yeast and beer. Here are the responses he gave me…
1. How long have you been working at NCYC?
Over 25 years.
2. How many yeasts related to brewing are currently in the database?
3. How important would you say your work is to the beer industry?
We work with a wide range of brewers from micro-breweries up to national and multi-national brewing companies. We are able to supply a unique quality control and identification system, which allows us to check the purity of cultures and identify any contaminants, as well as having state of the art Safe Deposit storage systems for brewing strains. For our customers we provide a very important service for quality control and back up of their strains – one of their most valuable assets.
4. Has there been any sort of increase in activity over the last few years?
We continue to steadily accumulate new customers and their strains and so each year tends to be slightly busier than the last. We have had a slightly higher number of enquiries from micro brewers over the past few years, but have not seen a consistent pattern of increase from any particular sector.
5. How have things changed with the influx of new breweries opening up in recent years?
As mentioned above, the numbers of smaller breweries opening recently has been reflected to some extent in an increase in enquiries and use of our services by these smaller concerns.
6. Do you have a favourite yeast?
It is difficult to pick out one yeast as a favourite because they all tend to have their own unique properties and are therefore all interesting in different ways. One of the most popular brewing strains is NCYC 1026 which is a well known ale strain originating from a UK brewery.
7. What do you do to ensure none of the yeast develops faults or oddities?
The yeast are stored by tried and tested methods which are known to prevent genetic changes. We use both freeze drying and, for our master stocks, storage in liquid nitrogen at -196C. This is below the temperature at which molecular changes occur and so precludes are changes arising.
After storage we are able to carry out ‘DNA Fingerprinting’ as a quality control method (which is also available as a service to our customers) and this allows us to find any genetic changes should they occur.
8. What is the oldest yeast in the database, when was it registered, and where did it come from?
The oldest yeast strains in the database were deposited in April 1920. These are mostly non-brewing yeast but also include some lager yeast from the Carlsberg Laboratory in Copenhagen.
9. What is the most recent yeast in the database?
The most recent deposits are again non-brewing strains and include many isolated by colleagues in the Maquipucuna cloud forest reserve, Ecuador.
Although we have some very recent safe deposit brewing strains in the closed collection, the last brewing strain deposited in the open collection was in June 2011.
10. What is your favourite beer?
Wychwood’s Hobgoblin. Also, Adnams Broadside.
Next month, an introduction to Hops