New fermenting fridge Qs

[bzwyatt]

Sorry if this is redundant. I've searched quite a bit and read/learned a lot, but not quite the specific stuff I'm looking for. So here's a quick thread about how best to utilize a fermenting fridge.


I got an 18-cubic-ft freezer up/fridge down fridge and wired up an STC-1000. I am in Los Angeles; I love the warm temps, but I am really relieved to have some better control now. And my wife is happy beer isn't in every closet in the house (the fridge was an early father's day gift).

- - I was hoping the freezer might end up in the range for lagering (48 to 60, roughly?) but it has been 40 or less most of the time I've been checking it. So I can't put LBKs in there to lager... and it isn't cold enough to use as an extra freezer for food... maybe I can have a store of hops and yeast and keep it in there? What do you do with extra cold storage space, if you have a similar setup? I don't want to waste the volume, you know what I mean?

- - I moved some conditioning bottles to the fridge, from my house. It gets in the hight 70s when I'm gone during the day, but the fridge is in the mid-sixties. So neither one is prime temp for bottles, right? 70 is the target? So which is better, a little warm, or a little cool? I want them in there, to consolidate my storage, and also to add some temperature-stabilizing volume, but if it is going to serioiusly reduce conditioning activity, it isn't worth it.

- - Also, as the second pic shows, I found a small piece of foam for a bit of insulation on the sensor. Does that look ok? My fermometer on the carboy is around 64, I hope the bucket is just a little warmer than that?

 

[ianhoopes]

This might be a situation where you will want to look into getting an external temperature regulator to set the temp in your fridge so you CAN do lagering. That's why I got my fridge.

 

[bzwyatt]

My STC-1000 is my external regulator. I meant that I thought maybe the freezer compartment would end up in a good lagering range when the fridge is kept at a good ale range.

Sometime I think I'll do some lager batches in the fridge, but it would be cool if I could do ales in the fridge and lager in the freezer. Not gonna happen though.

 

[BigFloyd]

Are you talking about lager fermenting range or cold-lagering after fermentation is complete? I generally ferment lagers in the 48-50*F range (d-rest at 61-62*F) and then later cold crash, rack to keg, and lager them at 35*C.

I'm afraid that, with a single unit fridge/freezer, you're going to have to pick a single use for it at any given time and stick with that. You can keep the fermenter temp (tape the sensor to the fermenter and insulate) at either a good ale temp, a good lager temp or even cold crash. When maintaining that temp of the fermenter, the freezer is going to fluctuate so much that you can't really make good use of it.

Your bottles will condition/carb at the cooler temps, but it will take longer. I'd suggest keeping them at room temp for 3 weeks and then moving them to the fridge for long storage.

 

[bzwyatt]

Thanks for the reply. Yes, I thought maybe I could use the fridge for fermenting ale and the freezer for fermenting lager. The cold comes from the freezer and gets pumped into the fridge as dictated by the controller, basically, right? So I started checking the temp in the freezer to see if maybe it would be in a good range to ferment lager beer. But it is too cold, and I have seen it fluctuate quite a lot, like you said. One time it actually was 48, but it dropped back down to 40 really quick.

As you can see in my pic, I have a carboy and a bucket for 5-gallon batches. I also have two LBKs, which would fit perfectly in the freezer. Would be cool to have that for trying out lagers, and I thought I might be lucky and the freezer would end up in that range. But it won't work.

I still want to use that space for something, so I'm trying to think what it could be good for...

 

[philipCT]

Some thoughts...

Not to state the [perhaps] obvious - but isn't there a separate thermostat for the freezer compartment? If so, I would just whack another STC-1000 in there and you will have complete control of the freezer compartment temps.

Looks like you have room for two separate fermentations - great!

I use a larger piece of cut-up beer-can koozie to wrap the temp sensor onto the carboy in my fridge/fermenter, but I think yours should do the job.

Mine allows a little air to mix in next to the carboy glass, and I think that's a good thing. I've noticed that when I first put a carboy in the chamber, the temp controller brings the chamber temp down real low (into 50's) in an attempt to get the beer down from 76 or so to 68. The beer temp then overshoots too low, and the predictable temp oscillations ensue until it stabilizes after a day or so. In order to avoid that, I set the temp on the high side initially (like 72F), and then step it down to where I want it over 24-48 hours.

Call it a poor man's PID.

 

[bzwyatt]

Perhaps I should look into the specifications of the model I have (18 ft Fridgidaire is all I know), but I don't think it (or any other fridge configured this way) works like that. I think that all the cold air from the compressor goes to the freezer. When needed, the fridge takes cold from the freezer, but not by engaging the compressor, just by taking cold from the freezer. That is why the freezer temp will fluctuate so much - it can get really cold when it is running, and then have enough cold so that the compressor doesn't actually have to come on for the fridge to take air and get down to the temp dictated by the STC-1000. The freezer is a resevoir the fridge borrows from, basically.

 

[philipCT]

Oh, did not know that. I guess that's why everyone uses freezer-only units (or in my case, a fridge-only unit - see my posts on the conversion for pics).

 

[BigFloyd]

Fridge/freezers have but one thermostat and one compressor. In normal usage, the temp in the fridge is controlled by air balance between it and the freezer.

With the STC-1000 or other similar controllers, you are simply turning power to the fridge on and off as needed to reach and maintain the temp you set on the STC-1000 (as read by the sensor). That's why you put the fridge on the coldest setting and let the digital controller decide when it needs to power on.

BTW- If your freezer is at 40-48*F while you ferment an ale in the fridge section, that would be a good place to chill beer after it has carbonated (so long as it doesn't get below freezing).

I've noticed that when I first put a carboy in the chamber, the temp controller brings the chamber temp down real low (into 50's) in an attempt to get the beer down from 76 or so to 68. The beer temp then overshoots too low, and the predictable temp oscillations ensue until it stabilizes after a day or so. In order to avoid that, I set the temp on the high side initially (like 72F), and then step it down to where I want it over 24-48 hours.

You can avoid that by simply pitching at or a bit below the temp at which you are going to start fermentation (usually in the low-mid 60's for an ale). Doing so is also a better brewing practice to help avoid production of off-flavors. Some ale yeasts (especially Nottingham) will stress above 68*F during active fermentation.

 

[FuzzeWuzze]

If its a side by side, would it be feasible to drill two reasonably sized holes, say 2 inches each between the freezer and fridge compartments? One near the top and one near the bottom.

I cant gaurentee it, but there should be no compressor lines between the two...but there's no real easy way to know.

Then just mount two fans, one blowing from the bottom of the freezer into the fridge, and the other blowing the hot air from the top of the fridge back into the freezer.

This + your STC1000 would in essence turn your entire fridge into a freezer, they would have shared temps which may not be what you need. But if your looking to lager i think its the only solution for your problem of your fridge being to hot, and the freezer being to cold.

 

[bzwyatt]

Yeah, I think I will just use the freezer for my beer fridge. I actually didn't think of that, haha. Partly because I don't have any beer right now, except the 16 gallons that is fermenting/conditioning. My fridge is outside, so I am going to have to rig some kind of lock. I was already planning on that, eventually, but if I have good beer in the freezer too, I really need to lock it...

Yeah, your build is cool philipmeese, you actually made the STC-1000 your direct thermostat. Mine is just wired to the power source for the fridge, like the other how-tos and is mentioned above. If I had two STCs, the fridge would be off, and the freezer would be on, so the whole thing would just be on.