Author Topic: Fermentation temp reduction  (Read 3731 times)

Offline markok

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Fermentation temp reduction
« on: November 28, 2013, 08:17:28 PM »
I currently have a Belgian Quad  in day 8 in the fermenter. Per the recipe I found (Denny's 400th Belgian Quad) I controlled the temp rise from 64 to 75 and am now holding it at 75 with active fermentation taking place. The recipe calls for pulling the temp back down which I am afraid to do because I don't want a stuck fermentation so close to finishing out. Does anyone have any experience with this? Why would there be any advantage to now allowing temp to fall back down before it's finished?
Thanks

Offline grathan

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Re: Fermentation temp reduction
« Reply #1 on: November 29, 2013, 07:21:40 AM »
If it's not finished and you eventually bottle they could explode... if you go cold enough to make the yeast dormant.


It's nearly impossible to say ferment for 'x' amount of time because of the unknown variables such as aeration and viable yeast amounts even with the constants of recipe and ferm temp. If you had a gravity measurement that would be very useful if you knew the target FG. Or just rely on airlock activity if not.


It's pretty rare to stop a fermentation early to lock in a specific gravity reading. I've never seen it in a recipe before.



Ahh, the recipe does indeed specify 1.026 before cooling
www.candisyrup.com/uploads/6/0/3/5/6035776/dennys_400th_-_variation_002x.pdf

So you've failed to mention if you've taken a reading or not. It also states the secondary temp of 50*F. This is well below the yeast's optimal low temp of 66 and will most likely drop out the yeast.
The recipe also states a 12 week seconday. Nearly all of the yeast will ahve dropped out. Notice how he doesn't say use priming sugar? It looks like the repitch of yeast is gonna go back to work on the remaining wort sugars.... very odd recipe.

Denny is pretty active on this forum and will most likely reply to questions here:
www.homebrewersassociation.org/forum/index.php?topic=7858.0


« Last Edit: November 29, 2013, 07:31:37 AM by grathan »

Offline Maine Homebrewer

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Re: Fermentation temp reduction
« Reply #2 on: November 29, 2013, 01:22:22 PM »
75 is a bit warm. At that temperature your yeast may create banana esters and other flavors that are generally avoided, along with fusel oils that can worsen hangovers. Maybe for that style those flavors are desirable, but not as a general rule. You'd have to take it down to 60 or lower before worrying about the yeast going dormant on you. Drop it back to mid 60s and you shouldn't have anything to worry about.
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Offline markok

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Re: Fermentation temp reduction
« Reply #3 on: November 29, 2013, 04:09:15 PM »
Ok guys thanks for the responses. I have now started allowing the fermenter to free fall to the mid 60s at 2 degrees per day.  I fail to understand the purpose in reducing the temp before FG though. BTW FYI my OG was 1097 and after only 45 hours the gravity was 1047. I thought that was pretty low for only two days. I haven't taken another reading since although I will next week to determine if it's time to transfer to secondary. Perhaps you could answer another question here. What is the advantage of secondary versus simply bottle conditioning at FG? I can think of two reasons not to and that would be oxidation and contamination. I don't have CO2.
Thanks again.

 

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