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Lager Fermentation

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SacredBrew

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So I started a lager a week ago. The first 3 days the 5 gallon carboy sat at 60 degrees F. Then for a day it sat at 50-55 Degrees F, Than for the last 3 days its sitting in my basement at about 43-45 degrees F. It seems as though the yeast has gone to sleep. It is not bubbling much at all. Is this because It was to much of a shock going from high to low temeratures? What can I do to get the yeast active?

Thanks so much

Jon
 

Tonedef131

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Yeast do tend to go to sleep when you cool them down, which is why most lager brewers pitch cold and then let it warm up slowly. If you cool them down too fast they will throw up a protein coat and essentially hibernate...then you are screwed. The general rule of thumb is no more than 3-5 degrees F changes per day. I like to keep it at 3 when cooling them down and just do 1 degree every few hours.

As for your case, I have no idea. Were they actively fermenting that whole time? Perhaps they are done. What was the OG and what is it now?
 

menschmaschine

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Have you taken a gravity reading? 7 days of primary fermentation may be enough. 60°F is really too high for a lager fermentation and 43 is too low (when you start high). Your best bet at this point (if you think a good portion of primary fermentation is complete) would be to raise it back up to 60°F for a diacetyl rest (assuming there are still some fermentable sugars left). Then slowly cool it to 50°F, rack to secondary, and slowly cool it to lagering temps.
 
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SacredBrew

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I havn't taken hydrometer readings. But I can say at 44-45 Degrees F the lager brew is bubbling every 18 seconds. Is this indicative of a slow fermenation that is happening? Should I let it sit down there at those temps until the bubbles slow down even more and then bring it up to the diacetyl rest? Or Would it help to bring it up to 50 F now to try to speed up the bubbles before I do a diacetyl rest?
 

menschmaschine

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If your lager primary fermentation is well into it... say 2/3 or greater done... you can warm it back up. The first 2/3 -3/4 of lager fermentations is the key time to ferment it cool because that is the time when the yeast will produce flavor-active compounds at higher temps.

44-45°F on a lager that started warm (yeast are used to fermenting warm) will slow it down. It will eventually ferment all the way out at that temp, but it will take a while. So, if you think it's 2/3-3/4 done, then warm it back up.
 

funkadelicturkey

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I know this post is old but I noticed the OP used a 5 gallon to primary, what kind of experiences have people had using a 5 gallons as a primary? I was thinking of using a 5 gallon on a lager tomorrow because I don't think my fridge with accommodate a 6.5 gallon carboy. What kind of head space is needed for the krausen? I understand that lagers usually have a krausen but that it is smaller, as small as 1 cm. Is this a good idea or a very bad idea. Starter in on the stir plate and I am wondering what I am going to do tomorrow...
 

944play

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I am brewing a 4-gallon batch of lager bound for a 5-gallon carboy. It should be simple enough to scale down your recipe, especially if you use brewing software.

I have never had a lager kraeusen climb higher than an inch or two, but I'm not taking any chances.
 

motobrewer

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if you use a blow-off you shouldn't have a problem. lagers don't typically have a big krausen.

heck, i put 5 gallons of ESB into a 5 gallon carboy. turned out great, actually was my best beer i've ever made.

you could always use fermcap.
 

funkadelicturkey

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thanks for the quick replies and advice, i am brewing a kit tomorrow (good idea but no ferm cap in the house) so I'll follow the recipe and leave a good 1-2 inches under the neck of my 5 gal. carboy, attach the blow off, cross my fingers, and have a homebrew.
 

funkadelicturkey

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Well, the lager never got a chance, yeast started, grains steeped, and I opened the (9 month old) extract and discovered mold growing in the bucket. Thought about brewing it anyways for a second and then dumped. Old moldy starting ingredients probably wouldn't be the best for making a beer than I am going to be waiting on for months. Oh well, back to ales...

here is a picture:
 
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