What is coldest temp possible in 'Son of Ferm.' or other 'ice-cooled' chillers?

I recently built a Son of Ferm. 'per spec'. I haven't yet tried it with a batch of beer, but I tested it with thermometer. I was able to get down to almost 40F. I ran it this way for a few hours. I only used five of those square reusable ice packs for this. I'm sure with more ice I could get it colder. I had trouble making clean straight cuts of the 2" foam when I built it, and could feel some cold air coming out in places during the test. I'm sure if I could seal it up well, it'd work great for lagering. Monty

Taping the seams should fix that.

For those who have not yet built one but are thinking of it, let me make a suggestion about how to possibly cut the styrofoam; this method worked extremely well for me when using thinner 5/8" styrofoam, but I have no idea how well it will work on thicker stuff. I took a butcher knife and sharpened it to where you could almost shave with it, and then I used my metal T-square as a guide, and I was easily able to make very nice, straight and even cuts.

Cheers.

Bill Velek -- remove the "--NO-SPAM--" from my email address

Some brands of woodburning tools and soldering irons include Styrofoam cutting adapters. My heating the blade a more uniform and smooth/straight cut is possible.

Bill,

Ken Schwartz says you can achieve down to 30 F below ambient temp. My experiences are consistent with that. I was able to cold condition a Kolsch beer at about 50 - 55 F in a room that was hovering around 80 -

I think you will have a difficult time using this system for lagering, at least with normal ice. The bulk of the heat absorbed by the ice occurs as the ice melts not as it's warming up from freezer temps, so the ice quickly warms up to 32 F and then stays there for a long time. That means 32 F is as cold as you can theoretically go. In practice you will never reach this temp because ice jugs have an upper limit as to how fast they can absorb heat and once that rate equals the rate at which the box is absorbing heat from the room, you are at equilibrium.

If you want to get colder, you have to use a liquid that has a lower freezing point. "Blue Ice" cold packs are one option (I think they also have a higher heat capacity?) but could get pricey for the number you would need. The other option would be to try and drop the freezing temp of water by adding salt. A mixture of 21w% salt and 79 w% water will freeze at -21C. Here's the phase diagram for water and salt:

If you try it let me know how it turns out. Don

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Yes, I know that, which is why I was just using the simple weight of the ice in comparison with the weight of the water, i.e., 10 pounds of ice rising from 0C to 10C should draw 10 pounds of water from 50C to 40C. I know that once the ice reaches 32F/0C, it will continue to absorb heat during its phase change to water, but that would be unimportant in my system unless and until the fermenter has already reached its lowest conditioning temp of close to freezing, and then the ice jugs would merely be maintaining the temp by offsetting any heat encroaching from the outside.

Thanks, Don. I thought about the blue ice packs, but not about making my own substitutes with brine. That would be easy enough to do. When I finally get this done -- if that ever happens -- I'll be sure to post the results. In fact, it will be interesting to see if, using frozen brine, I'll be able to get a small amount of water to freeze in the upper compartment, just as a test. I'm still hung-up on collecting info re thermostats. :-(

Bill Velek -- remove the "--NO-SPAM--" from my email address

A quick update on my SOFC.

It works great (for what it is)!

When I first tested it, I didn't seal the top and front panels with the wood molding and weather strip called for. I've since done this and am currently down to 35F air temp and 39F beer temp. And I still have a lot of room to go lower on the thermostat.

The thing about these is they take longer to bring the temp of the beer down (which is a plus to keep from shocking the yeast). Once the beer reaches temp, though, I think the mass of it helps keep the thing at a consistant temp. I found Igloo ice packs at Target for under $2. I keep about eight in at a time, rotating another six once per day. The ones I take out are still faily frozen. Pretty good insulation, I'd say.

I guess if I added up all my receipts on this, I may have enough for a used fridge. Then again, my electrical bill would be much higher. And it was kinda fun to build.

I'll let you know if my lager freezes up :)

Monty

snip

How low does your thermostat setting go? Can you provide details, such as brand name and model number, and where you acquired it and how much it cost?

Thanks.

Bill Velek -- remove the "--NO-SPAM--" from my email address

I got the cheapest bi-metal I could find (Honeywell) at Home Depot, I think $15. The only thing is, it's for heating only, so the logic is reversed - it turns on when the temp goes lower. So I had to follow the instructions on the SOFC website regarding adding a relay into the circuit (about $3 plus $1.50 for breadboard).

Also, the adjustment lever has stops at each end of its travel, so it wouldn't normally go low enough. I just cut the stops off with snips. It can now swing way past what would be freezing, I'm sure.

It collects quite a bit of condensation in the ice chamber, so I drilled a hole in the bottom and ran a piece of tubing to allow runoff.

I have seen pretty expensive thermostats that go low on McMaster.com, but still wonder which one is being used.

Of course, I just spent too much time f>

snip my question re the thermostat in Son of Fermentation Chiller

Thanks for the info, but I'm going to try to rig up something different

-- mainly so that I can control and monitor the temp from the outside of my chiller -- which means a probe (at least one) and probably something digital.

Hmmm. I never noticed that much, but perhaps it was because of my particular design. And for what relatively small amount that there was, I just have my ice containers sitting on a tray and I use a cloth or sponge to wipe up the condensation.

Cheers.

Bill Velek -- remove the "--NO-SPAM--" from my email address

I'll check it out.

Grommets?? You don't need no stinkin' grommets. ;-) I assume that the grommets are for something different than a chiller or brewing beer.

When I built my chiller, I used a sheet of white styrofoam which cut very easily. Pink? Are you speaking about spun-fiber-glass batting? I'm not much of a handyman, so I don't go to those places too often.

Cheers.

Bill Velek -- remove the "--NO-SPAM--" from my email address

The grommets are for the wood pole (dolly?) and the pink stuff is pink styrofoam - from the same company that makes the spun fiberglass stuff...

I think the grommets were to somehow lock the top and front panels using some kind of pins. I just put an empty carboy on top to keep it sealed.

The pink 2" is real nice high density rigid polystyrene. It doesn't crumble like the white bead-board.

A Ranco or other controller would certainly work great to control the temp from the outside - at a cost of about three times what all the other components were. Slight overkill for an icepack-driven chiller! Of course, once you have that, you're half way to getting a used fridge and having a real fermentation chiller!

There's many ways to skin a cat, many ways to chill a lager. Hope your's tastes as good as I know mine will. Cheers!

I use the pink 2" polystyrene. One 4'x8'sheet gave me everything I needed, which made it convenient to use. It also holds the temps exceedingly well, although I'll admit that I caulked the living hell out of every joint, and I do not have a removable front panel on mine. I figure I can lift a carboy over a wall.

I use a cheap Wal-Mart-obtained Hunter digital thermostat for mine. I DO keep the thermostat inside the SOFC. To monitor temps, I have a small digital indoor/outdoor thermometer sitting on top of the thing. To change temps, it's a 10 second process, so it really isn't that inconvenient for me to keep the thermostat inside. I use Velcro tape to hold down the top, combined with cutting it ever so slightly oversized so I have to force it down. I maintain temps well enough that once fermentation has slowed in primary, it goes hours without budging even a tenth of a degree.

My cheap thermostat goes to 40 degrees. I've not yet tried to lager with it, so I don't know if it'll obtain that with only two one-gallon jugs of ice. I see no reason to believe it wouldn't, though.

All told, I have far, far less than $100 in parts. In an apartment where I really can't keep a spare fridge or chest freezer, this was my best alternative.

Monty wrote: snip

I see; well, I'm not that familiar with those chillers, so I didn't recall the grommets.

My white bead-board doesn't get much exposure or handling, so I have no problem with crumbling. The exterior of my chiller is wood-paneling on the front and sides, and heavy corrugated cardboard in the back.

Well, I started out making a frame to hold my conical that my in-laws gave me as a Christmas gift, and since I couldn't figure a way to use evaporative cooling, I decided to enclose and insulate it, and chill it in a similar fashion to the Son of Fermentation Chiller. Aside from that, I really don't have a place to put a chest-freezer that would get the stamp of approval from my wife right now. Plus a chest-freezer is not tall enough for my conical. Likewise with a refrigerator -- difficult to find a place for a great big frig that can hold just a single conical.

My chiller will be a good way for me to make and try a lager before investing in more equipment.

Bill Velek -- remove the "--NO-SPAM--" from my email address

One of the great things about home brewing for me is getting to analyze a problem/situation/opportunity and figuring out how to make it work for me. What is it the Marines say, "Adapt and overcome."

This forum is ideal because you usually get a whole range of solutions to pick from. As long as you keep in mind the end goal isn't gear, it's beer!

Keep on brewing!

Monty