Fermentation cabinet - Cutting a hole in steel?

So, I bought a giant steel cabinet. Like, the office supply type. It is around 24"d x 46"w x 78".



I plan to use the bottom for two (14gal drum) fermenters (or 3-4 Ale Pails) and I plan to have a shelf half-way up the cabinet.

The top half will be used to store corny kegs (both containing beer that is conditioning, and the sanitized ones that are ready to fill.)

I debated doing this backwards - fermenters on top, kegs on bottom, but since cold air drops to the bottom, I thought the fermenters would be better below. Especially since a 14G drum full of water is so heavy.

I plan to caulk the seams of the cabinet to prevent excessive air loss, and then I plan to insulate the *outside* of the cabinet using pink foam and tape.

I am going to use a window A/C unit to provide cooling power, and I already own a Johnson controller (or is it a Ranco? I forget.) to control the temperature with.

My first question is, how do I cut an A/C sized hole in this unit? What tool(s) should I use?

It's already indoors and in a carpeted room (not shag, but still carpet) so I will need to be careful about creating too many sparks or I could have a little situation on my hands....

Tool-wise.... I have a corded Dremel. I have a corded jigsaw. I have a battery powered circular saw (ok, it's my wife's).

I do not own an angle grinder. Or really anything else useful.

Temperature wise... my primary goal is to have a good, reliable 64*F for ales.

Eventually (and once I get a feel for the cooling output and airflow inside the cabinet) ... I could see creating individual zones, adding in an ETC11000 or some other controller, paired with some 120mm fans for air flow. I like the idea of a cold spot and a warm spot, so that I can lager in the coldest zone and still hold an ale fermentation in the warmer zone.

I don't care deeply about the temp the corny kegs are held at. I suppose if they (like the lagering zone) are also in the 40*s that would be a nice bonus - but I'm fine with them sitting comfortably at 55*F-60*F during conditioning.

So in a way, this forces the question of... do I mount the A/C unit low in the cabinet, or high in the cabinet?

I was planning low, as I don't know how I'm going to support the A/C without bending the cabinet wall...... some sort of brace will clearly be needed.

I would mount it at a height that it is not blowing directly on one of the fermentation vessels. Computer fans would be helpful for circulating the air to get equal temps throughout the chamber. You way want to use strut for support (see strut build thread on the forum) although 2x4's would probably work. Remember to get the thermostat probe outside the chamber, bypass it or adjust the temp (if your unit has a calibration screw) so you can get your temps below the usual 50 degrees that AC units are usually set to.

I didn't know you had to modify the A/C unit. I thought it was just a matter of setting it to HI & COLD and letting the Johnson/Ranco do the work?? That sucks, I didn't realize it was going to be even more tinkering. I've got five window A/C units laying around the house un-used. Two have digital controls so they would not be ideal for the ferm. chamber. (I'm thinking that, when the Ranco cuts power, it will of course power off the control panel and I'll have to press the "Power" button each time.) But the other three are all physical controls. I'll get model numbers and pictures when I have a minute. Maybe I will luck out and one of them will be easier to modify than the others.

I haven't cut holes yet. I could always caulk the seams and use this cabinet for grain storage instead. Not sure what I'd use for fermentation control then. I hate the idea of having to use a chest freezer to control my ferment temps, I don't want to lift buckets in and out of it. And I can't really afford to buy multiple upright freezers. And I am certain I want to control more than a single fermenter at a time. Two simultaneous would be my absolute minumum - IF I ever build my eBrewery, that is. I'm still brewing on my crappy pulled-together outdoor furniture with no shelter, it's one batch at a time for the time being. If I could give up on needing two batches at-a-time, then an upright freezer could be an option. Still more than I hoped to have to spend though.

I am starting to kick myself though because the entire reason I bought the steel cabinet is because it was supposed to be easier than trying to build a cabinet enclosure myself out of wood. I really do not have any tools or workspace to work inside of so any size of project is immensely frustrating to me. All I'm trying to do is emulate a walk-in cooler in a smaller form factor. This seems like it should be stupidly easy. *sigh* I'm not having a very good day and am finding myself in a very ugly headspace. I don't know what my problem is right now. :/

If I need to avoid blowing air directly on the fermenters, then it sounds like mounting the A/C unit up high is a no-brainer. It would blow directly on to the corny kegs, and then cold air would drop (or be blown by fans) through the shelf and into the lower zone.

I suppose I could plow ahead with building it in the hope that whatever A/C I choose to install will cool as far as I want it to. If it doesn't hold the temp I want, I could dive into modifying the thermostat at that point??

Adding a vertical separation panel in the middle of the bottom zone would create two distinct zones. Once it's split into two zones, It could be as simple as two ETC1000's - one for each cabinet - and each one controlling a 12v wall wort + CPU fan *or* 120V Muffin Fan. When a zone gets too warm, the ETC kicks the fan on, and blows cold air from the keg chamber into that zone. Then if the keg chamber warms too far as a result of cold air loss into the zone, the keg chamber cools itself via the A/C unit.

Don't forget about catching the condensation drips from the AC unit. You could run some duct from where the cold air comes out of the AC to the cabinet. Just make sure the unit is secure where you place it. A good cfm case fan, or duct fan, could help pull the cold air into the cabinet too. You also could be better off insulating the inside. Keep in mind how the door opens. Now think about the additional thickness there from the insulation. See the issue yet?

I was planning to do the outside of the unit because if I add 2" foam on front and back, it gets reeeeally tight inside there - the 14gal drums are out of the question at that point but the Ale Pails would still barely fit.

I instead planned to do the outside, and just bevel the edges that would normally pose a problem when opening/closing the doors. My **hope** is that, since the unit "lives" indoors in a basement room, that I hopefully will not have to cool anything "that far" and some insulation inefficiency would be tolerable - as opposed to say a free-standing outdoor walk-in cooler that is exposed to the elements.

Then again, I've also thought about ditching these 14g drums on account of how big/heavy they are when full. If I use them, I will have to fill them in-place and then rack beer back out of them.

Oh god. I'd forgotten about needing a post-fermentation pump. AUGH. Stupid drums. Buying those was perhaps a bad idea.

This is what your ac unit will likely look like disassembled. The copper temp probe on the front of the unit is the issue. If the temp of the room it is in will be higher then 50 degrees, then all you have to do is bend it around so it stays outside of the chamber. Since the unit thinks it is >50 degrees, it will keep cooling. If it is going in a cool room (40-50 degrees) then you are going to have to modify it to get to lager temps.

Chriso said:

I was planning to do the outside of the unit because if I add 2" foam on front and back, it gets reeeeally tight inside there - the 14gal drums are out of the question at that point but the Ale Pails would still barely fit.

I instead planned to do the outside, and just bevel the edges that would normally pose a problem when opening/closing the doors. My **hope** is that, since the unit "lives" indoors in a basement room, that I hopefully will not have to cool anything "that far" and some insulation inefficiency would be tolerable - as opposed to say a free-standing outdoor walk-in cooler that is exposed to the elements.

Then again, I've also thought about ditching these 14g drums on account of how big/heavy they are when full. If I use them, I will have to fill them in-place and then rack beer back out of them.

Oh god. I'd forgotten about needing a post-fermentation pump. AUGH. Stupid drums. Buying those was perhaps a bad idea.

Click to expand...

You could always switch to sanke kegs and use a CO2 push to move the finished beer.

MtnBrewer- That is the probe? Oh lawd. I'm sorry for such an overreaction. I'm feeling a little panic prone for some reason and am ready to start flipping tables over and burn all of my fermenters. Sorry for the unintended crazy.

I'm certain that one of the two A/C models I have laying around has that style of probe, and the room it is in is pretty stable between 60-70*F depending on the season.

Golddiggie-
That's right!! I forgot about CO2 push. I think that is what I had settled on - it will use up more CO2 than I hoped, but is preferable to $200+ for a peristaltic pump. The two plastic drums that I bought have gaskets in their lids (screw-top) and so I assume they would take between 2-5 PSI without bursting open.

BUT, that being said, I have strongly considered whether I should sell the drums locally to another brewer who would use them, and give up on having 10gal-sized fermenters, simply sticking to Ale Pails until I have things, uh, shall we say 'under control'. (Meaning making up my damn mind.)

What kind of drums are you using? I have recently picked up (3) 15 gallon malt drums from my LHBS. I plan on fermenting 11-12 gallon batches in each of them. Do your drums have a 3/4" small and 2" large bung on top? If so, I have already solved your problems...

Not sure if your "hole" question has been answered but you may out your circle with a Sharpie drill a 3/8" hole close to the hole and finish cutting with a jigsaw with thin metal cuttin blade

Huaco- I have two of these: http://www.ebay.com/itm/13-gallon-B...=&orig_cvip=true&rt=nc&_trksid=p2047675.l2557
Yours sound like the blue "Carboy" type drum. I've heard lots of good things about those.

Mtn Brewer- I looked into the Strut stuff and it looks intriguing. I assume I will need an angle grinder or something equally decent to cut the strut into pieces, correct? Hm. I could definitely see building the brew stand out of strut instead of lumber, though. I will have to keep that in mind for the full indoor brewery build.

Packer- Jigsaw, THIN metal blade, not thick. Got it. I'll plan to buy a new blade (decent brand) when I get around to this step. I know for a fact that I only own the sample pack of blades that came with my jigsaw, and I am certain the metal ones are chewed to hell already, from my prior attempt at using said jigsaw.

Yeah, I got mine from my LHBS. Sell yours and get some of those from your store on the cheap!

My LHBS only sells pre-packaged extract, no dry or liquid in bulk. I could, however, get the blue drums from eBay. Hum. I will think on it. Going to eat some lunch, then take some cabinet pictures.

Here are some pics...