The effects of hot and cold temperatures on Homebrew

Temperature is incredibly important when it comes to homebrewing, it has an effect on pretty much every aspect at every stage so you do have to be very aware of it. Our kits come with instructions including what temperature is best at each stage, but here there will be more detailed explanation of each step.

What is the actual effect temperature has on our homebrew? Heat is what helps stimulate reactions, which is all cooking really is. But you have to use the right temperatures to do this. In the cooking stages we want to bring out substances such as sugars from the malt or bittering agents from the hops. This makes it much easier for them to be absorbed into the liquid. But for both stages we do want different temperatures, why? Well the enzymes for the mashing stage (which is where we soak the malt) will start to die above 75C, and in the boiling stage will most certainly die. For the boiling stage a reaction to get what we want out of the hops could happen, but it would be a much slower process. So temperature is incredibly important for this stage.

The same principles apply to fermentation, the yeast is causing a reaction and the right temperature is needed. Mainly we need the yeast to react with water and sugar to create alcohol. However, yeast dies at 30C+ which is a much lower temperature than the enzymes reacting in the mashing and boiling stage. If this happens you can try cooling it and then adding more yeast. The fermentation will start up again but it won’t be quite perfect. Yeast will also stop working at low temperatures, sub 20C and you’ll get no reaction. This is easier to fix as placing your ale in a warmer area (but not too warm) like an airing cupboard should get the reaction going again.

20-30C is where yeast is most happy, but you also don’t want it fluctuating too much. You may find that where you store the ale in the summer won’t be good enough for the winter as the temperature gets much lower. If it goes below 20C if may struggle to get back to the correct temperature without some added heat and it goes above 30C for an extended period your yeast is dead. So it is very important you find a warm stable area to store your homebrew.

Once bottled a precise temperature is not as important, however it does still have an effect. First you need the secondary fermentation to take place, even more still ales want some carbonation so just like before need the yeast active. But then you need cooling, this is too stop the yeast from being as active and to cause the lumps of protein in your ale to float to the bottom. Being less exact you don’t have to worry so much about this stage but temperature still plays an important role.

Throughout the process temperature plays an important role in brewing. It is something you do need to think about and if you ever have a brew not work it is the first thing you should check. Especially in the colder months make sure your homebrew stays warm enough.