Johnson A419 question

[Ungoliant]

Okay, so my temp controller is hooked up to an 8 cu ft chest freezer, and the probe is in a thermowell in a 6 gallon carboy for my current batch (Double Chocolate Oatmeal Coffee Stout, using WYEAST Denny's Favorite 50). After some research and long deliberation (yes, I'm aware of all the pros/cons) I chose this setup, so as to directly control the temperature of the wort.

My settings are:
Cooling
Cut-out
SP: 67
Dif: 1
Ofs: 2
Asd: 6

So, here's my question: given one temperature probe in this set up.

Would a second batch with a similar yeast fermentation temp range as the first batch essentially be kept in the same range with the controller controlling the temp of the first batch?

I would expect a bit of an offset, but not enough to harm the second batch.
Here's a pic for those who care



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[cram]

In short, yes, it would. The difference would come from the heat generated by yeast activity, which is especially relevant during the first handful of days after pitching the yeast. So if your temp control is set at 67* in the first batch, and you brew another batch, but leave the probe in the first, then the temp might be ~5 degrees more in the new batch.

 

[Ungoliant]

Thank you for the awesome answer!

So should I also assume that a batch in primary fermentation would have the same effect on a batch in secondary fermentation enough to ruin it?


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[m1k3]

How often are you brewing?

If it was a week later I'd just move the first batch to a room in the house to finish out. After a week at 67F you can ramp up to 70-75F.

I'd prefer to control the second batch but not at the expense of a decreasing ferm temp on the first batch.

The other option is to brew two batches in one day and ferment them together.

 

[Staylow]

I built my own fermentation chamber with a single temp probe from an STC-1000. When I brew a new batch, I move the probe to the new brew. After watching through several batches now, I've never noticed the temp of the older brew drop more than 2 degrees as the new one moves through active fermentation. 2 degrees, to me, is an acceptable swing. I think you'll be fine.

 

[Ungoliant]

Well I actually haven't brewed for about two years, until this last weekend.

I had to take a pause for a while due to work/changing my brewing setup and adding equipment. I was mostly just curious if I could do multiple batches with offset cycles, using my current method.

I think doing a dual batch day wouldn't be too bad, though. I can't really complain about a 10 gallon brew day.


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[m1k3]

You could get creative selecting yeast stains. Use a strain that works cold first.... Nottingham will ferment in the mid 50s.
Then the next week use an strain that likes mid 60F.

You could brew for several weeks in a row by doing a Belgian next and then a Sasion.