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Temperature Control

Temperature Control

One of the most important things in homebrewing is temperature control of your fermentation.  

Controlling the temperature of your fermentation is key to getting the best out of your yeast, and getting the best out of your yeast means getting the best out of your beer.  

There are two main categories of yeasts; ale yeasts and lager yeasts.  

The majority of ale yeasts prefer warmer fermentation temperatures (18-22C). 

Lager yeasts prefer cooler temperatures (8-13C).  

These temperature ranges vary depending on the yeast strain and the characteristics that the brewer wishes to get out of the yeast. 

On most packs of yeast you will find the ideal temperature range listed, this is the temperature range that the yeast will perform in specification/style.

When we are talking about temperature controlling fermentations, the aim is to keep the temperature of fermentation as stable as possible.  If the temperature dips too low (i.e. over night), the yeast may become dormant as it is too cold to keep working. 

If the temperature becomes too hot, the yeast can become stressed and produce fusel alcohols and other funky flavours.  

In extreme cases where the temperature goes above 35C+ you can kill the yeast, resulting in an incomplete fermentation (as well as all those off flavours).


There are many different ways that brewers can control their fermentation temperatures ranging from inexpensive and/or manual options to more expensive and automated options.

Brewers just starting out often find a cupboard or room with a cool, stable temperature.  Some augment this using blankets for insulation (in the cooler winter months) and some use water baths with ice bricks (in summer months).  These can be very effective in maintaining a consistent temperature throughout the fermentation period but require regular monitoring and adjusting.

For brewers looking for a more automated solution, temperature controllers are becoming far more accessible and feature rich.  While this option is more expensive than a water bath or a couple of blankets, it doesn’t have to be an option that costs several thousand dollars either.  

Pair a temperature controller (which will set you back $69.95) with a second hand fridge (which you can pick up for less than $100 or if your lucky for free) and a heat belt or mat and you can set your fermentation temperature within less of 1C and the temperature controller does the rest whether it’s 4C outside or 40C.  

With all temperature controlled solutions, brewers need to remember that they need to control the temperature of the wort or beer that is fermenting and not the air around the fermenter.  

Beginner brewers often think that setting your room temperature to 20C (for example) is adequate, however, the process of fermentation is exothermic (produces its own heat), so it is possible that you think your fermentation is sitting at 20C, when in fact it is more like 21-23C.  It may not sound like much, but if you want to get repeatable, consistent beer at home, you need to treat your yeast right.

If you have any further questions about temperature controlling your fermentations, please email or come in and have a chat to one of our friendly staff.

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