Temperature

[divingdavey]

Hello.... I'm currently fermenting a wine kit and am keen to have a go at some beer.

Temperature seems to be quite important to fermentation, how important is it and what are the best temperatures. Since I will be brewing at home room temperature obviously varies from night today let alone week to week.


Thanks

Dave

 

[WelshPaul]

Most ale yeasts that I have ever used are pretty hardy things and will happily ferment between 17-25°C. I'd be wary if the temperature strayed over this though as they can produce some off flavours.

 

[divingdavey]

Thanks for the info :)

I doubt the temperature will get to above 25 degrees, what happens if it dips below 17:?

 

[Hawks]

Welcome ....

yes, temperature is very important, it can impact what the yeast is producing and give you undesirable tastes and smells ( as well as fusel alcohol if you ferment too high ).

The ideal temp for most ale yeasts will be around 18c ( the yeast itself should tell you, as lager yeasts for example ferment much cooler ).

As its the temp of the liquid, an overnight drop of a few degrees will have little impact.

As you progress there are varying ways of maintaining a steady temp from aquarium heaters in the FV, to stand the FV in a bucket of water you can control or build a cupboard with a temp controller. At this time of year though you should be fine :thumb:

 

[graysalchemy]

If it dips below 17 it will be slower.

But what you actually need is a temp between 18-21 above that you will certainly get off flavours and fusel alcohols, 25 is way to high. It is actually the growth phase of brewing which is most critical as this is when a lot of the precursors of esters and fusels. Between 18 -21 the esters are produced these are the fruity notes found in English style bitters and pale ales, the closer to 21c the more esters you will get and below 18 less Esters will be produced. However when you go above 21 the yeast switches metabolism more fusels will be produced. Fusels produce the hot solventy flavours which may be appropriate in a good brandy but certainly not in an English bitter.

Another point worth mentioning is that fermentation is exothermic so it is easy for temps to rise out of control especially if you are trying to control the temp with a little bit of heat ie heater or fermentation cupboard.

:thumb:

 

[divingdavey]

Many thanks :)

 

[divingdavey]

Sounds like it would be best to err on the cool side even if it takes a bit longer.

 

[Hawks]

You don't want too cool or the yeast will drop out and you could get a stalled fermentation, but as its exothermic if you only know the room temp go on the cooler sides of the temps mentioned as the wort will be a degree or two warmer ( assuming you are making a standard 5 gallon ( ish ) amount. :thumb: