Careful Cellaring, Part 1: The Quality Assurance Process for Creating Clean, Living Beer

Before a beer leaves our brewery to go to your cellar, or your bottle share, or your mouth, it has a very busy schedule as it gets approved for its release into the world. We've explained previously how working with sours comes with its own trials and tribulations, but for cellared & aged beer month at The Bruery we think it's time to delve deeper into the steps it takes to produce and release clean, cellarable, living beer.

As many a craft beer lover may know, the brewing process requires a ton of cleaning and serious attention to sanitation. This attention to detail doesn't just apply to a single brew day. To make sure a beer can be sold and consumed as it was intended to taste, every part of every brew endures our quality assurance process. It takes all levels of staff to pull this off, including our brewers, lab ladies, packaging, cellarmen, and managers. We love to make experimental ales, but with each unique experiment comes new challenges for our team to monitor.


To create clean, cellarable beer, we divide the beer production process into six parts. Each of these parts are divided into smaller quality assurance tasks and repeated at different frequencies. Certainly there are challenges added when special ingredients and barrel aging gets thrown into the mix. We'll be addressing the barrel side of things later with our wood cellarman Brett Richman, but until then, here's a broader overview of the quality assurance measures that happen with each and every brew at The Bruery.

Raw Materials

Our water, yeast, and incoming raw materials are routinely inspected for a several things. Chlorine levels in water are checked, as too much chlorine in brew water can result in a band-aid-like flavor in the finished beer. Our yeast viability, cell count, and certificate of analysis are routinely checked so yeast must have certain percentage of viability, be free of beer spoilers and have an appropriate cell count. Additionally, breweries may perform raw material inspection to look for any wild grain, foreign material and acrospire, holes in hop packaging, and oil or foreign material in CO₂.

Brewing

During brewing, mash pH and temperature are monitored by each brewer to ensure proper utilization of hops and allow proper enzyme conversion. Wort is inspected on several points including attenuation, original gravity, pH, lautering, conversion, and micro, which requires collection of an aseptic sample after the chiller to determine cleanliness of the line and heat exchanger. These samples are plated on both an aerobic and anaerobic plate supplemented with cyclohexlamide. Micro must show zero beer spoilers at this point. For milling, we are preparing to use grist sieve analysis to produce profiles of grist to ensure a proper grind for optimal extract yields and lautering times. For any raw material and adjunct lot change a brewer will calculate the estimated ingredients needed to produce a certain volume of wort of the desired gravity. This would be tracked along with the measured original gravity in order to complete grist calculation. Husk volume analysis requires isolating husks using a sieve, then weighing and measuring to determine the volume in terms of ml/100g of grist.

Fermentation

Each yeast pitch is tested at this stage again, as is the gravity, cell count, pH, and sensory (by smelling) of the green beer in each fermentor. Fermentations will be monitored at Fermentor Full (FF), After Treatment (AT) and End of Fermentation (EOF) for micro cleanliness. The yeast and green beer micro must show zero beer spoilers.

Racking

ABV, pH, CO₂, micro, dissolved oxygen (DO), and sensory testing occurs here. DO levels for a finished bright tank must be less than 50ppb, the micro plating must show zero beer spoilers, and the ABV per style is determined before the beer is released to packaging.

Packaging

This stage is broken into five parts and has over 20 points of inspection, the most of all stages. The packaging team is a vital part of the QA process. Inspection of bottle quality & graphics, laser coding, dilution, fill levels, CO₂ levels, rinser operation, rinse water, pH, visual & taste analysis are just a few parts of the packaging routine. As beer is bottled, three are pulled from the beginning, middle and end of a run and plated on both aerobic & anaerobic plates with supplemental cyclohexlimide. If the beer is a barrel aged beer it also gets plated on media specified for pedio & lacto growth. Once bottles are finished, they are also inspected to verify no low fills, poor lid seals, leakers, incorrect graphics, incorrect/missing codes, illegible or incorrect graphics are visible. For kegging, a dilution check and the pH are tested for different keg sizes at different frequencies.

Miscellaneous

Environmental cleanliness, taste panel, and equipment maintenance make up the final segment of our quality assurance process. Brewers must take the time to walk through the brewing, cellaring and packaging areas and identify possible microbial issues and clean them up. They also inspect hoses, pumps, gaskets and any frequently used equipment for damage and biogrowth. Hoses, clamps, gaskets and connectors are kept off the floor as much as possible and soaked in sanitizing solution & cleaned manually. Our whole management team participates in the taste panel on packaged beer & special releases biweekly, where beer is evaluated on factors including appearance, aroma and taste several times before it is cleared for release. Bright tank & pre-filtered beer is tasted as needed. Equipment maintenance is performed on our alcolyzer and Zahm CO₂ meter monthly, our DO reader twice a week, and performed with every use for our pH reader, microscope, and UV spectrophotometer.

Since we make some beers that we want to cellar and enjoy many years down the road, we also set aside certain bottles for stability testing at different time intervals as needed. Doing this lets us see how the beer is performing, what kinds of bacteria may or may not be present (there are certain bacteria that are there on purpose, in the case of sour beers), and can give us an idea of how a beer will age.

In order to test the longer term stability of each beer, we set aside bottles in our "hot cellar" that is kept at 80º and rerun micro and analytics testing on each beer. This is done two weeks after its brew date, then again one month after its brew date if no problems were present at the two week mark.

Even when all these inspections and tests are done, that's not the end of the story for our beer. We are a brewery that makes unpasteurized and unfiltered beer, which means our beer is a living product! As a beer matures, it changes as it ages -- ideally for the better, but sometimes this is not the case. An undetected brewery-side infection or consumer-side improper storage conditions can alter the well being of an aging beer ... But that's another blog to come.

Read more of our cellaring series:

• Careful Cellaring, Part 2: The Importance of Temperature
• Careful Cellaring, Part 3: The Threat of Light

Further reading:

• The Microbrewery Laboratory Manual - Part II: Bacteria Detection, Enumeration, and Identification
• The Siebel Institute's HLP ImageBank
• Quality Control in the Brewery