How long should I hold fermentation temp down?

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J2W2

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Hi,

I'm brewing an Altbier with Wyeast 1007 (German Ale). I pitched it on 09/18 at set my refrigerator to 57 degrees. By 9:30pm I was getting around 4 bubbles per minute (bpm) in the blow-off tube.

The fermentation peaked on days 2 and 3, with around 25 bpm. It also had blow-off sometime in this period.

The bubbles in the blow-off tube started dropping from there, and by day 5 it was down to 7 bpm. I raised the temperature to 58 on day 7, 59 on day 8, 60 on day 9 and 61 on day 10. The bubbles slowly dropped to 4 bpm.

I've held it at 61 degrees, and I'm still getting 3 bpm on day 12. My original gravity was 1.061; I have not checked the gravity again as I don't like disturbing it and removing the blow-off tube until gas production pretty much stops.

I've never had a yeast stay active this long. It's in a temperature controlled refrigerator, and in a glass carboy, so I don't think this can just be CO2 coming out of solution. These are bubbles coming out of a 1/2" ID blow-off tube, at a constant 3 per minute, so it's not like this is just a little random gas coming out.

It's hard to see in the carboy with the film on the glass from the blow-off, but I think it still has krausen on top. Should I leave it at 61 as long as it shows activity, or should I let it raise now (maybe around 70) to finish?

Thanks for your advice!
 

DurtyChemist

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White labs says the ideal fermentation temperature is 65-70 so I'd let it sit around there if you can. Depending what you're using to take the temperature will change stuff. If you're taking the ambient temperature I'd leave it. If you're taking the temperature of the wort I'd increase it.
 

Gavin C

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I've made 1 altbier.

Pitched at 56F

Fermented at 58F till 1-2 degrees plato above anticipated FG (take a gravity reading once the krausen falls) and the set the beer temp to 68F and allowed it to rise passively.

Couple of days at 68F ensured complete attenuation prior to cooling, fining and kegging 2 weeks after pitching the yeast. WLP036 in this instance.

Here is the profile with approximate timings entered in the planning phase. No racking other than to the keg.




One question. Are you measuring beer temps or the ambient air temps in the fridge? It is of course beer temp which is important so forgive the nonsense question its just that some folks prefer to monitor ambient which removes most of the control of your fermentation profile.

Edit: Short answer. Till 1-2 degrees above plato seems to work well for lagers and hybrids.
 
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J2W2

J2W2

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White labs says the ideal fermentation temperature is 65-70 so I'd let it sit around there if you can. Depending what you're using to take the temperature will change stuff. If you're taking the ambient temperature I'd leave it. If you're taking the temperature of the wort I'd increase it.
This is a Wyeast product. Their site has the following:

Flocculation: low
Attenuation: 73-77%
Temperature Range: 55-68° F (13-20° C)
Alcohol Tolerance: approximately 11% ABV

So I'm right in the middle of their temperature range. I'd been told this yeast can produce sulfur off flavors if it ferments above 62, so I've held it below that. Although I recently saw a post that said the opposite - sulfur flavors at lower temps; hopefully that one is not correct.

Tomorrow will be two weeks, so I think I'll take the blow-off tube out, get a gravity reading, and let it rise to 68-70 if it's around the expected final gravity.


One question. Are you measuring beer temps or the ambient air temps in the fridge? It is of course beer temp which is important so forgive the nonsense question its just that some folks prefer to monitor ambient which removes most of the control of your fermentation profile.
I'm using a Johnson controller to regulate the temperature, and I have the probe attached to the side of the carboy. It's covered with a couple of wide layers of neoprene to insulate it from the ambient temp. Not a perfect setup, but since the probe can't be submerged, it's the best I can do.

Thanks again for all the help!
 
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J2W2

J2W2

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I took my first gravity reading today (two weeks after pitching). I've actually been using a refractometer this year after getting one for Christmas.

The refractometer said my original brix was 15.0 and my original gravity was 1.061. My reading today was a brix of 8.4. Using a refractometer calculator, my calculated final gravity is 1.016 and my ABV is 5.728.

I'm actually slightly over on my ABV - I was shooting for an ending batch size of 5.5 gallons and it was closer to 5.25. I'm also within 0.002 of the estimated final gravity that Beer Smith had.

So, if it's not done it's darn close. I'm going to let it rise to the 68-70 degree range to finish.

Thanks again for all the help!
 

TheMadKing

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I brewed an Alt with 1007 about 2 months ago. So here's what I learned

my ferm was about 65 the whole time and I have no issue with sulfur flavors.

It took a long time to finish, I had it in primary for 3 weeks

This yeast WILL NOT drop out of suspension unless you cold crash, it's a beast

It produces some funky flavors (sort of like wet dog, or barnyardy) and a tartness that will mellow nicely with lagering. After bottling/kegging I'd let it lager for at least a month before tearing into it.

hope that helps, my alt turned out great and I'm about halfway through it.
 
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J2W2

J2W2

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I brewed an Alt with 1007 about 2 months ago. So here's what I learned

my ferm was about 65 the whole time and I have no issue with sulfur flavors.

It took a long time to finish, I had it in primary for 3 weeks

This yeast WILL NOT drop out of suspension unless you cold crash, it's a beast

It produces some funky flavors (sort of like wet dog, or barnyardy) and a tartness that will mellow nicely with lagering. After bottling/kegging I'd let it lager for at least a month before tearing into it.

hope that helps, my alt turned out great and I'm about halfway through it.
Thanks for the advice. I plan to let it sit another week in the primary, around 68 degrees, and then I'm going to rack I into a secondary for another three. I plan to take it down to 40 or so for a couple of weeks and then add gelatin and drop it as low as I can in my refrigerator (it might not go much below 40).

The primary has a lot of trub in it - I got more out of the kettle when I drained it than I would have liked. I'm hoping to get a nice clear beer by using the secondary and cold crashing with some gelatin.

The sample I pulled for the refractometer has a nice color, aroma and taste (for a warm, flat beer), so I'm hoping for the best.

Thanks for your advice!
 
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