Quality Control & Testing Beer: Tips from Pros
Behind many great brews are scientists testing and tasting beers in the lab. In fact, every beer — be it commercial or homebrew — can benefit from better quality control. Two beer lab experts share their advice.
Brewer: Luke Chadwick, Bell’s Brewery in Kalamazoo, MI
We run three testing programs at Bell’s: analytical, microbiological, and sensory. All are carried out to ensure consistency and conformance to the original design of the brew (and, most importantly, to the expectations of our customers). Analytical (chemical/physical) testing includes the measurement of alcohol, bitterness, carbonation, color, pH and diacetyl. Extensive microbiological testing is carried out 1) to ensure the viability and vitality of our yeast and 2) to ensure no contamination has occurred anywhere in the process. Sensory testing encompasses all of the above and it is, at the end of the day, our most important analytical tool.
Sensory analysis is the go-to technique of the homebrewer. Everyone at every skill level can become a better taster. Virtually all of the potential defects that brewers are concerned with have a unique sensory signature. Most everyone has the ability to recognize any given defect with a little bit of training and LOTS of practice. On the flipside of that, most everyone is anosmic to one or more sensory stimuli. In addition, any given person on any given day could have sensory fatigue and not detect something that would normally hit them like a smack in the face. That is why if you are serious about using sensory analysis as a quality control tool, it is imperative to maintain a panel of trained tasters, and to constantly challenge them and “keep them on their nose.”
By far the most common flaw I find in my line of work is inconsistent yeast/protein levels. Our ales are unfiltered and unpasteurized. The nature of yeast is such that it tends to flocculate into clumps. We employ a dizzying array of procedures designed to standardize the amount of yeast that makes its way into package, but still discover packages — both bottle and keg — that contain more yeast than we’d like.
If you want to perform better quality control on your homebrews, or if you want to do this kind of work on the professional level, here are my recommendations.
1. Join the American Society of Brewing Chemists (ASBC) (www.asbcnet.org/) and Master Brewers Association of the Americas (MBAA) (mbaa.com) and attend as many meetings, conferences, and webinars as you can. Sign up for the online Methods of Analysis from ASBC and incorporate methods into your operation wherever practical.
2. Take a class at the Siebel Institute. All of these organizations have tons of offerings.
3. Join the Brewers Association (brewersassociation.org); attend their “power hour” webinars.
4. Tour breweries. The lab — in my humble opinion — is the most important stop on the tour! If you can get a few minutes with lab folks, that’s a great time to get informed answers to very specific questions.
5. Sensory, sensory, sensory. Hone your tasting skills. Have your friends blind test you. For example, let a beer get infected and see how many times your friend can dilute it and you still detect the spoilage. There are many different beer spoiling organisms — get familiar with the flavors and aromas that the spoilers in your area impart to your brews.
6. Keep excellent records of the procedures and raw materials you use. Lot numbers, age, storage conditions, temperatures — anything that changes from one brew to the next can impact the final product.
Brewer: Jim Crooks, Firestone Walker Brewing Company in Paso Robles, CA
Many of the routine tests we do in the Firestone Walker lab can be easily done at the homebrew scale. The merits of a quality brew start with healthy yeast and without a microscope and a hemacytometer to look at viability and density, you are just guessing about the quality of your yeast. This tool, as well as with other tools like refractometers/hydrometers for checking gravity, thermometers, pH strips, beer color wheels and basic water testing kits can all be purchased inexpensively ($30–100).
For the advanced homebrewer, setting up a field micro lab can be a little more involved but not out of the question. A homemade laminar hood and sterile sampling technique is the basic backbone of a small scale micro program. WhiteLabs.com is a great homebrewing resource that offers a premade media test kit bundle that can be geared toward either anaerobic or aerobic bacteria as well as wild yeast. The White Labs site also offers a number of educational links as well as actual pictures of what bacteria look like when growing on the media. The potential cost savings to be had by doing a little micro investigation of your process can be well worth the cost of the tools, versus the potential cost of losing a few batches to poor sanitation technique.
Some of the common brewing flaws we catch in the lab are %ABV and color deviations from batch to batch. Although slight color deviation is not a pressing quality flaw, most people drink with their eyes and color is one of the first noticeable attributes a customer will see so we take it seriously. Rushing a sample through the program can also give rise to careless mistakes and often wastes more time by raising questions due to erroneous data. When in doubt, repeat your analysis.