Using the cool fall temps to cold crash?

I want to try cold crashing, but I currently do not have fridge space to cold crash 5 gallons of beer that are in my carboy. But, I was thinking, I might be able to cold crash by just putting the carboy outside, considering the cool fall temps. My plan is to cold crash starting tonight (Tuesday) and bottle on Saturday. So 3.5 - 4 days of cold crash.

I checked my weather outlook for Kansas City. The lowest it will get is 33F. The highest during the day will be 67F.

1. Good idea or bad idea? And why do you think so?

2. This is an all extract batch, with only 8 ounces of specialty grains for color/flavor. The rest of the fermentables are 6.6 pounds of light LME. Is there any advantage to cold crashing extract batches? Or is it only beneficial for AG batches?

Thanks!

1) not really sure. you definitely need to have it covered so it won't be exposed to UV light if you decide to try this. the fluctuating temperatures might not be ideal for the beer, but i'm not sure why. i think the idea of cold crashing involves sustained cold temps to get the yeast and other proteins to drop out of the beer, i don't know that overnight cold, then warming all day, then overnight cold will have the same effect, but it might work...

2) either.

I do this in my unheated mud room all the time. (Well, all the time in winter.) The advantage is that I have a shelf in there that allows me to set the fermenter up high for siphoning, which means I don't have to move it and risk swirling up all the stuff that just dropped out.

Will you carry your fermenter back inside to bottle? My only concern would be swirling stuff up while moving it.

My guess is that with the temps you listed, you beer will get to about 48F or so. Because of the thermal mass of 5 gallons of liquid, it will resist cooling at night and heating during the day and equilibrate in between the two extremes.

I have no empirical data on what will actually happen, but I don't think you can expect it to get down at 40F

android said:

you definitely need to have it covered so it won't be exposed to UV light if you decide to try this.

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Yeah - I will definitely put a black t-shirt on that puppy and put it in a shady spot on the patio if I do this.

JonM said:

Will you carry your fermenter back inside to bottle? My only concern would be swirling stuff up while moving it.

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Good point. But, if it is in a fridge, wouldn't you have to move it out to transfer to the bottling bucket/keg anyway? Maybe I will be super extra careful if I move it back indoors. Or just lift it up on the patio table to transfer to the bottling bucket. Good point! Hadn't thought about swirling up the trub!

broadbill said:

My guess is that with the temps you listed, you beer will get to about 48F or so. Because of the thermal mass of 5 gallons of liquid, it will resist cooling at night and heating during the day and equilibrate in between the two extremes.

I have no empirical data on what will actually happen, but I don't think you can expect it to get down at 40F

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This, too, is a good point. Sounds like cold crashing isn't worth it above a certain temp which you seem to indicate is 40F.

If you do end up doing this and some trub is stirred up you can just let it sit for a few hours to let the little bit to fall back out of solution. If you are bottling you can always just cold condition them in the fridge for a week after your regular conditioning period for the same clarity effect - only difference will be the amount of yeast at the bottom of your bottle

Ive found that even cold crashing at 48 overnight drastically reduces the amount of yeast that make it to a bottle.

Yep I do this all the time in my unheated (but insulated) garage during the winter. In the dead of winter it usually stays right around 35 degrees, perfect for chilling.

I would be a bit concerned about temperature fluctuations this time of year though. You might want to do this for only a night or two to minimize the fluctuations. You will see a dramatic difference after even one night.

thanks for all the replies! I am going to give it a shot.