Beer yeast does not get the credit that it deserves.
Fans of Craft beer will discuss beer at length but few really give yeast, our true blue collar brethren, much thought. Brewers will discuss their recipes, malt, water treatments, and temperature regimes at length, but yeast often take a back seat. This lack of interest affects the both the professional and home brewer alike.
All of the ingredients that go into a beer have an impact on the beverage’s flavour, with some having a bigger impact than others. This contribution is dependent on the style of beer that is brewed. A simple lager has little flavour contribution from its yeast when held up to a Belgian Dubbel, but using a compatible yeast variety is compulsory for the taste and aroma of both.
To the experienced palate, many yeast characteristics are a very important part of a beer’s distinctive charm. From flavours and aromas, to byproducts and attenuation, the contributions from yeast to beer are a necessary part of the experience. From the banana, clove and even bubblegum components of a German wheat beer to the subtle sulphur tones and clean crisp bite of a good lager, certain yeast derived notes are essential to a good beer. When they are missing, muted or overdone the educated consumer can often experience a beer that is ‘not quite right’ for its style.
When making a beer, brewers make a variety of decisions on the products that will go into the final product. Many will agonize with water treatments, grain choice, and hop selection and utilization. Few though give much thought to yeast choice, and the impact that it can have on their product.
On the homebrew scale, many brewers are afflicted with the ‘kid in a candy store’ syndrome, where they change yeast (and often other variables) frequently, often before developing a deep understanding of the item in question. Many homebrew supply stores and even yeast manufacturers prey on this desire for new by regularly bringing out ‘special release’ products.
On the professional scale though, we see many breweries locked in to a small selection of yeast strains (many with only a single strain for most beers, save specialty brews) and learn it well, often ignoring newer or possible better performing strains. While a somewhat necessary evil in bulk production, this can lead to beers that miss the mark of the purported style. Imagine trying to make a full flavoured beer with a neutrally flavoured strain – the beer may be passable, but to the experienced taster something may be noticed as missing.
Understanding these elements, the concerns to the end user are those much more apparent. These concerns are;
- Select a strain suitable for the beer to be produced, taking in to account that there are often multiple choices with variable degrees of overlap
- Determine how the strain works in the equipment and processes of the brewhouse
- Is the supplier competitive on price, quality and support
- What are the characteristics of the finished beer
The last few years have seen a dramatic increase in the number of yeast supply companies. They are all competing for a market share, and while the customer base as a whole is increasing, by adding new yeast start-ups into the mix consumers should take note and be wary. Below is a partial list of popular Craft yeast suppliers.
The workings of yeast culturing and supply companies operate in a grey area of sorts, and this is to some degree a necessary evil. (how they obtain their original yeast cultures is rarely discussed as a result of this grey area, and one that is a disservice to the brewer) The typical model for the production and sale of a yeast strain is something like this;
Obtain a yeast strain
This is one of the more ethically problematic pieces of the puzzle. For a variety of reasons many producers are reluctant to release the details of where or how strains have been obtained. Some do give hints that can be used by the brewer to determine the origin of the strain. The more detail that can be given about the strain is a benefit to the brewer, thus putting the two somewhat at odds.
Determine its essential characteristics
The strain in question is tested under laboratory conditions to determine ideal usage ranges and performance. Often results in the brewhouse are different to those in the lab, requiring the brewer to make process and usage adjustments despite thorough lab testing by the supplier.
Bank the strain in a stable manner
The yeast suppliers must maintain stable supplies of the master and working cultures that follow ideal storage methods as determined by experts and experience. This service is a large part of what the brewer pays for – taking the place of an in-house ‘yeast wrangler.’
Grow the strain up to usable sizes and package appropriately
This is the bread and butter of yeast supply companies. In addition to finding the variety of strains, they must grow up tiny cultures into workable amounts and then package them effectively for transport to breweries and retail locations.
Sell and ship the product
Shipping yeast can be a tricky proposition as it is ideally stored very cold, yet it often has to go a very long way. Several retailers will therefore utilize products and methods to ensure the yeast arrives as healthy as possible at its destination.
Issues to consider
Is the producer able to create enough of the product?
For the homebrewer small samples are needed, but to a large packaging brewery often a sample must be brought in and ‘grown up’ in house in order to keep costs reasonable.
Is the product quality able to meet expectations in a reproducible manner?
The yeast in question must work the same way every time in order to produce beer that is up to the expectations of the brewer and the drinker.
Provenance – where does the yeast come from? Is it unique to the producer? Is it a proprietary blend?
This cannot be stressed enough. Yeast supply companies are always on the lookout for new yeasts to harness and produce for their customer base. There is much literature on obtaining wild cultures from the environment, but the number of yeasts that are unique strains from proven breweries of historical significance is finite. Thus we would expect that regions from around the world would have numerous strains of wild yeast, but there are only so many cultures that have been selected for their performance in historical breweries from around the world.
This means that until they start cross/selective -breeding for new strains, producers are all offering very similar strains to each other. The variable of when exactly they obtained their strains may change its performance slightly, but the number of strains available will still be limited. There were only so many historical English or German or Belgian breweries to harvest from, so we should expect to only see so many strains from them. Yet troubling to sober thought though, is that many yeast companies are popping up.
With many of these new yeast start-ups, how can the consumer be sure to get a truly unique product? Without seeing some sort of genetic testing we simply cannot be sure. More importantly, when brewers begin buying and using custom blends of organisms, they are entering a world of irreproducible beer unless they start with a fresh blend each time. The reason for this is explained simply – the variety of organisms that make up the blend reproduce, work and survive at differing rates thus changing over the course of a single brew, let alone multiple batches. We must remember that reproducibility is key to successful brewing.
Would an alternate strain work better?
This is a trade-off of sorts that was mentioned as being an issue between homebrewing and professional breweries. Often a professional brewery gets ‘locked in’ to certain strains, while the homebrewer often does not learn the yeast in question as well as could be hoped. The answer for both is simple: Brewing multiple test batches and altering a variable at time is the scientific way to proceed. Of course research from peers and published materials is always helpful to shorten the experimental process. One can’t determine a better/best strain without carefully testing all the strains that apply.
A Final Thought
With the end user accepting the claims of the producer on faith alone, one walks the slippery slope of falling prey to salesmanship and snake charmers. Are the differing product claims believable? Should they be taken at face value if provenance isn’t discussed?
As genetic testing is becoming increasingly available and some yeast companies are starting to delve into providing the services, we should expect them to start giving us more specifics on the products that we use.