Producing a quality product consistently is the key to success! Every brewer has the capability of monitoring process and product to determine level of consistency and quality. Obviously a home brewer will have a different level of quality control than a bottling microbrewery; however, the level of consistent quality should be the same.
Every brewer can and should monitor and evaluate critical points in the brewery. Basic record keeping is essential to establishing consistency and developing a basic QC program. There are three major points to controlling quality: Equipment, Wort, and Yeast Management.
Know your system and its limitations. Many brew systems have weak points that can potentially cause problems. Scratches, dead ends, and shadow areas that do not receive adequate exposure of chemical must be avoided. A consistent cleaning and sanitizing regimen must be followed.
It is important to be certain that you are using proper concentration levels, temperatures, and contact times for your chemicals. It is impossible to sanitize a surface that is not clean; all organic matter must be removed before sanitation can occur.
The term sanitized is not always well understood. Sanitized does not mean sterile. Good sanitation and sanitary practices lead to limitation of microorganisms but does not guarantee that they are eliminated. A smooth surface that has had all of the organic matter (such as dead yeast or wort residue) removed is relatively easy to sanitize because there is no protection or food for microbes. In contrast, a rough surface or a surface that has not been adequately cleaned is very difficult to sanitize because microbes are able to find protection from your chemical cleaning. Use of hot water as a sanitizer should be avoided. Thermophiles can survive high temperatures, so use of a no rinse sanitizer or a sanitizer followed by a sterile water rinse is essential.
In general, the most common sources of infections are heat exchangers and old cracked hoses. Each of these locations offers cracks and crevices for microbes to take shelter in. Regular inspections of surfaces are essential for consistent results. The heat-exchanger should be adequately cleaned and sanitized following each brew session.
Knowing that your equipment is well maintained, clean, and regularly inspected will form the foundation to consistent, quality beer. In the event of a contamination issue, a well documented cleaning program will help to take some of the guess work out of determining the source of contamination.
Now that you are confident in your equipment, it is time to focus on your wort. If your equipment is clean and well maintained, it is relatively easy to produce stable and consistent wort.
Adequate record keeping will allow you to track the consistency of your wort. It is very important to monitor and record as many points as possible such as original gravity, pH, length of boil, percent evaporation, timing and quantity of hop additions, addition of any coagulants, and any other relevant data. Once again, if you have good, consistent records it becomes much easier to trouble shoot in the event of a problem.
Wort must be boiled vigorously in order to achieve a proper protein break and to kill any possible infecting microbes present. An 8-10% evaporation in 1 hour is a good target to shoot for, but each brewery will have slightly different capabilities. Adequate protein removal prior to running into your fermenter is important for beer stability and consistency. Use of kettle coagulants and a well designed whirlpool will aid in the removal of excess protein.
It is important that a brewer regularly check the fermentability of the wort produced. A very simple and effective method is a forced fermentation test. This test can be performed by any brewer with or without a lab. The forced fermentation test consists of aseptically pulling a wort sample (post heat-exchanger) into a sterile sample container and inoculating with a very high yeast cell count. Agitate the container often. Check the gravity after 36-48 hours to determine terminal gravity. This test will give you a good idea of where your fermentation should finish. If your main fermentation does not reach the same level as your forced ferment, you know you have a problem in the fermenter (pitch rate, temperature, oxygenation). If both your main fermentation and the forced ferment finish out of spec (too high or too low), you know that you have a problem on the brewing side (mash temperature, times, crush, ingredients) .
Your equipment is properly cleaned and maintained, your wort is consistent and stable, now make sure all of your diligence and hard work are rewarded with consistent predictable fermentations resulting in great beer.
Yeast performance is tied many factors. Everything that you do during the brewing process will have an effect on the yeast that is converting your sweet wort into beer. Once again, good record keeping on the entire brewing process will help to maintain consistency and to locate inconsistencies that could be causing a change in yeast performance or beer quality. Pitch rates and oxygenation were covered previously, but the importance of these two factors cannot be stressed enough. Adequate pitch rates and oxygenation will help to minimize the impact of inconsistencies in the brewing process. Fermentation tracking will also allow a brewer without a lab to maintain good, consistent fermentations
Documentation and Tracking
The importance of good documentation cannot be over emphasized. A microscope is not need to keep good records. Information can be kept in a logbook or on computer file, which tracks all information pertaining to the brew. The following are suggestions for documentation and tracking information.
- Strain ID
- Lot # and MFG Date
- Package Size
- Beer style, volume, date
- Temperature at pitching
- Starter Information
- Pitching rate in cells/mL
Good fermentation records are valuable when evaluating yeast performance over a period of time. Brewing specs per batch:
- Wort cooling/Run in time
- Wort aeration
- Fermenter volume
- Yeast pitching details
- Gravity and temperature daily
- Time to half gravity or set target (i.e. 5 °P)
- Final gravity
- Cooling time and date
- Forced ferment sample