# Belgian Yeast Fermentation



## Patriack (18/3/17)

Hi everyone, first post on here so sorry for the newb question! I've been brewing a lot of Belgian style beers lately and have have good results starting fermentation at a low temp and gradually ramping up using a fridge. My question is how do I let the fermentation temp climb naturally? I have an internal probe (via thermowell) that controls my thermostat, should I set the temp low and then just turn the fridge off and let the yeast do its thing? Or set an ambient temperature if it's particularly hot/cold outside? Would love some feedback! Thanks heaps. Pat.


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## mr_wibble (19/3/17)

I've been considering that question too, except for wheat beers.

The idea (for what beers) is you start at (30 - <final temperature>), so if I want to finish around 18C, that means I should start at (30 - 18) == 12C. Source: “German Wheat Beers” (1992, Brewers Publications)

Something I read (I can't find the link now, but it was a German/English blog on homebrew) suggested that 3C per 24 hours was an OK temperature increase rate.

With that in mind, the only way I can see to achieve this with an STC-1000 controlled fridge is to manually adjusting the temperature limit morning and night. I guess if you're at home on the weekend you could do in 0.5 degree stages - if you had nothing better to do.
There is an excellent post here on the amount of temperature generated in fermentation, the relevant part is a graph.





So a 1.050 batch is going to give you about a 3C temperature increase.

However, this does not indicate the rate of temperature change. A couple of things I read on this forum suggest that the highest temperature production is during high krausen. This may also change depending on your vessel too. Maybe do a test-ferment in your fridge initially cooled, but then turned-off, monitoring with a temperature logger?

Now, on the other hand ~

The whole point of Belgian yeast strains is the relatively more prominent ester & phenol production. This happens at higher temps and when the yeast is stressed. So if keeping your fermentation cool gives you better beer because there's less "Belgiany" character, perhaps ferment with a bigger pitch, more aeration, etc. etc -> all those things that lead to happy yeasts and cleaner fermentation.


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## manticle (19/3/17)

Hi Pat,

If you're getting good results doing it the way you are, what's the reason for changing?

I think a lot of people overestimate the ester and phenolic levels in quality commercial Belgian beer.


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## fungrel (19/3/17)

manticle said:


> Hi Pat,
> 
> If you're getting good results doing it the way you are, what's the reason for changing?
> 
> I think a lot of people overestimate the ester and phenolic levels on quality commercial Belgian beer.


I agree. If you are after repeatability in your process, the less time you spend tinkering with temp changes the better.


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## Patriack (19/3/17)

Thanks for the input and ideas! I guess the reason I'm looking to do things differently is just to learn, see how the ferment behaves without me manipulating the temp manually, maybe the yeast will express itself differently? I am always looking to try different processes in all aspects of my brewing and it's great to have a place to get advice and suggestions from other like minded, passionate people. Cheers!


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## malt junkie (19/3/17)

Depending which stc you have(model number on the pcb inside) it maybe able to flashed (reprogramed). In which case you could program the ramp rise. There are also other projects such as Brewpi (the older one) that also allow for such programing. I'd really love to throw in half adozen links but I'm on the phone.
Ferment control and repeatability are a big step toward consistent quality beer, though what manticle has said rings true for me regarding Belgians.


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