Raising fermentation temperature

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rowyourboat
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Raising fermentation temperature

Post by rowyourboat » Wed Sep 16, 2020 1:06 pm

I'm making a Belgian Dubbel (all grain recipe kit) with a Lallemand Abbaye Yeast.

The kit instructions say ferment at 18° and raise to 21°

How would people recommend doing that? Leave at 18° for several days then raise sharply near the end, or notch it up by 0.3° every day or so? Its a high OG so expecting to let it ferment at least 10 days

It's my first brew using a fridge and controller so not had the flexibility to do anything like this before. Would appeciate anyone's comments or experience from doing similar.

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Jim
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Re: Raising fermentation temperature

Post by Jim » Wed Sep 16, 2020 2:18 pm

I would say you should raise the temperature once initial vigorous fermentation is dying down.

The idea is to get the initial stages of fermentation done at the lower temperature (to reduce excessive 'fruity' flavours) and to raise temperature to ensure fermentation gets fully completed.
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Kingfisher4
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Re: Raising fermentation temperature

Post by Kingfisher4 » Wed Sep 16, 2020 3:02 pm

The Belgian high gravity beers I've made (they happen to have been MJ not Lallemand yeast, but likely to perform in the same way) I've kept them at 18 degrees for 2 or max 3 days then allowed to "free rise" as the initial fermentation is exothermic, then kept them at the maximum temp reached or tweaked up to maintain relatively high fermentation temps; about 28 degrees C ultimately from memory.That max temp would depend on your yeast but needs to be near it's upper range limit.

As Jim said, initial taming reduces excessive ester formation, but you do want these esters to develop for the Belgian character. Key is apparently not to let temp drop once higher temp is achieved and fermentation is well under way otherwise a stall at too high an FG can result.

rowyourboat
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Re: Raising fermentation temperature

Post by rowyourboat » Wed Sep 16, 2020 5:52 pm

Thanks for the info both of you.

It's definitely vigorous at the moment. Once it starts to bubble away less I'll let the temperature start to rise.

The yeast range is 17-25° according to the lallemand website so I'll maybe let it go a little higher than 21° and see what happens... not up to 28° though!

I have a heat belt too, so should be able to avoid a temp drop even if the weather cools over the next few days.

Never made a strong Belgian before so keeping things crossed this turns out well.

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