Temperature control of craft beer

Hands down the most important environmental control in brewing is temperature, including both hot and cold side of the process.  Hitting the correct temperatures spans the entire brewhouse process, most importantly mash temps in order to make available the appropriate fermentable sugars that are needed later for yeast fermentation.  In the fermentation, temperature control is critical to maintain proper yeast performance as well as control the production of secondary flavor and aroma compounds resulting from yeast metabolism.

Because this is such a critical step to producing great tasting beer, having the appropriate control is a necessity at every brewery.  When, how, and what to do with those measurements is nearly just as important.  Here are some things to consider when comes to temperature measurements and temperature control.

Spot measurements

These measurements referring to spot checking the temperature of your craft beer from time to time to make sure you are in the appropriate range.  This is an important quality auditing tool, to take random measurements of your temperature controlled procedures in order to validate that equipment is working properly.  Develop this into a routine (random routine testing) and you have the workings of a basic quality control program.

Point measurements

Point measurements are useful when you need to hit a particular target, as with strike temp in the brewery.  This will require your temperature gauges to be fast and reliable so that you can be sure whatever you are reading is correct.  These measurements will require accuracy to +/- 1 F, since they are often looking at a range rather than an exact temperature.

Constant measurement and control

Continuous temperature measurement occurs in two major places within the brewery process – mashing and fermentation.  In mashing, you want to maintain tight control of your temperatures to ensure you are reaching saccharification for activating necessary enzymes for the breakdown of starches into fermentable sugar by way of alpha- and beta-amylases, as well as staying below the denaturation point for these enzymes.  For beta-amylase is most active between 140 and 149 °F (60–65 °C) and denatures above 167 °F (75 °C), while alpha-amylase is optimal at 158–167 °F (70–75 °C) and denatures above 176 °F (80 °C).  In the practical sense, most brewers are using a range of 145-158 °F, depending on how much beta- or alpha amylase activity is desired.  Since this span is fairly narrow, it is critical to be able to measure and control these temperatures within a small range, otherwise there is a risk of creating an unfermentable wort.

The second major area for constant monitoring is fermentation.  Yeast is heavily dependent on proper fermentation temperatures in order to maintain consistent performance and secondary flavor and aroma compounds.  Even a change in a few degrees, particularly during the early stages of fermentation, can dramatically alter the production of ester and fusel (higher) alcohol compounds, completely changing the sensory aspects of the beer.   In addition, temperatures at later stages of the fermentation such as crashing beer to remove yeast from suspension or increasing the temperature of lager fermentation a few degrees for diacetyl rest will impact overall beer quality.  Maintaining strict temperature control at this stage is absolutely critical and will require control of glycol (or other temperature elements) to be held within +/- 0.5 degree Fahrenheit to preserve the most effective regulation.

Although much of brewing requires a “feel” for the art, much in the way of cooking, there are still important fundamentals that need to be upheld.  Temperature control is one of those essential fundamentals that can truly make or break your beer, and with a few simple tools, one of the easiest to manage.