Underground fermenter

[shotgunner]

I do not have space for dedicated equipment like a fridge for fermenting.

Living in SoCal a basement is not an option.

I am considering making a "fermentation coffin" in which I can utilize underground temps like a basement.

1. Dig hole
2. Place waterproof floor
3. line walls with moisture proof materials
4. seal walls to floor
5. walls rise 3-4 inches above ground
6. build insulated & tight fitting lid
7. put in fermenter
8. put on lid

I have checked underground temps. On the northside of my home I see 56F all year round. While the temp is not adjustable it is super consistent. I can then tune my recipes to my liking.

I checked for similar threads but did not find any. Has anybody tried this?

 

[TyTanium]

I like it! Make sure it's rodent / bug proof. And make sure it doesn't become a bathtub in the rain.

 

[Diver165]

Doesn't really matter where it ferments. So long as the temp is consistent with your style of beer...have at it!

But wouldn't it be a helluva lot easier to buy a used freezer or fridge and temp controller, than to dig a big enough hole in the ground for all that? Unless you're just shooting to be different and that's ok too.

 

[ekjohns]

dont hit a gas line!

 

[shotgunner]

But wouldn't it be a helluva lot easier to buy a used freezer or fridge and temp controller, than to dig a big enough hole in the ground for all that? Unless you're just shooting to be different and that's ok too.

Nope. Not trying to be different. As I said, I don't have the space for dedicated gear.

PLUS! Digging the hole requires no brains or electricity. I like to make my designs so that physics control the things. Physics is perfect and failproof.

PLUS^2 If the grid goes down, I won't care!

 

[shotgunner]

make sure it doesn't become a bathtub in the rain.

That is why I designed the walls to finish above ground. It allows the rain to pour over the lid onto the ground and definitely NOT into my chamber. Also, this helps exclude vermin.

I am a little worried about condensation inside. This can be mopped up.

My biggest concern is blowoff. I'll solve that problem if when it happens.

I am thinking about 6" cinder blocks for the walls (no rats!), then finish them off with spray on bedliner. For the lid, I'll do insulation board to plug the hole and keep the "above ground temp influence" to a minimum. Cover that with some sort of weatherproof material (roofing?), put on a drip edge and I am done.

I just measured a carboy, that plus fermlock and I have 24". A 30" deep floor should do it.

Now do I make it big enough to bottle condition too? :cross:

 

[Tinga]

why not just put a ferm chamber outside?

 

[Huaco]

are you planning on a hoist or something to lift that carboy out of an awkward place? Really wouldn't have to be more than a little tripod with a pulley. If you anchor a pulley to the top of the wall, you could actually pull up on the rope to lift the carboy out.

 

[TyTanium]

I like it! Two thoughts -

I'd have to think eventually you'll end up with some sort of liquid in there, and the bottom could end up wet, slimy, moldy - may be worth digging another 6-12" and backfilling with gravel to your original floor height, then giving the floor a slight slope with some drainage, then elevate the carboy on some sort of false bottom. Might not be necessary, just thinking out loud.

Asphalt roofing shingles work great, but they do absorb significant heat, so either insulate well or add some vents between your chamber lid and your roof lid (mini attic of sorts)

 

[Diver165]

Well, if I was gonna bust my ass digging, I'd dig once and have it big enough to ferment, condition and store what I want. Do a google search on digging a wine cellar. A lot of people dig free standing cellars. Some dig ones in with the opening through the floor of their house (which I thought was cool as hell).

This should be interesting. Post pics!!!

 

[horseinmay]

I love this idea. Go for it. I hope you are putting this on the shady side of the house. I'm sure a small space could get pretty hot if the sun beat down on it for long enough. Personally, I would not do this in glass. I ferment in corny kegs, and if I didn't currently rent, I would consider it myself. Be careful. The last thing you want to do is drop a full carboy into your beer well and have it break. Good luck.

 

[shotgunner]

why not just put a ferm chamber outside?

reasons already discussed. Please read the bit about off grid, power out...

 

[shotgunner]

I like it! Two thoughts -

I'd have to think eventually you'll end up with some sort of liquid in there, and the bottom could end up wet, slimy, moldy - may be worth digging another 6-12" and backfilling with gravel to your original floor height, then giving the floor a slight slope with some drainage, then elevate the carboy on some sort of false bottom. Might not be necessary, just thinking out loud.

Asphalt roofing shingles work great, but they do absorb significant heat, so either insulate well or add some vents between your chamber lid and your roof lid (mini attic of sorts)

Lots of great advice!

I guess I have to be careful. This can become an obsession. Yeah! Of course, I have to explain that to you guys! LOL

Googling DIY dig a wine cellar turned up nothing else of interest. Diver I wasn't planning on digging an entire cave.

I have considered construction further. Perhaps concrete backer board for the walls. Dymondwood for some structure...? Maybe the thin cinderblocks will be OK.

I like the pea gravel overflow. I can put waterproof insulation as a "soft floor" but no seal it tight, allowing room for washing into the gravel.

@Huaco. Regarding the lifting. I had not considered the 60# carboy worth worrying about. 60# is well within my abilities. All I have to do is lift if from the chamber to the sidewalk, while on my knees. I might be fat but I have the abs! The rest is simple. When I get too old to heft it out of there a simple tripod will easily block and tackle it out!

@Horse I mentioned earlier, northside of the house. Our northern hemisphere homes always have southern sun exposure. NO light, no lightstruck beers. My northside grows mosses. It is cool and damp. BUT above ground it is much warmer than underground.

Everybody, thanks for the advices and the concerns!

Wow!

 

[jaz5833]

Where I grew up in Central VA my father had a "well house" that as you can tell by the name housed the well. However, he built it to store garden products and meat during the hunting season. It was at least 5 feet in the ground and had block walls which extended about 3 feet above ground and had a fully insulated peaked loft/attic that also served as a storage shed above it. Even in VA during the summers he had to use a small window AC unit to keep it cool enought to store potato's and such.

Having lived in San Diego for the past 27 years and having quite frequently dug in the ground around my house during the summer months my guess is that unless you dig at least 6 feet down, you're not going to get much cooling effect.

Sounds like WAY more work than necassary.

 

[Zamial]

I am not trying to discourage you but when you insulate said box, you will be insulating the cold out of the box. It will gather condensation inside like mad and you will end up with a stinking mess, more than likely.

FWIW I would buy a small chest freezer, put a lock on it and leave it outside. If you have room for a giant hole you have room for a chest freezer.

GL

 

[shotgunner]

I am not trying to discourage you but when you insulate said box, you will be insulating the cold out of the box. It will gather condensation inside like mad and you will end up with a stinking mess, more than likely.

I do not remember indicating I was insulating it. If I did, that was a mistake. The design has progressed to uninsulated with a "floor drain" that allows moisture and blowoff to make it to out of the chamber.

FWIW I would buy a small chest freezer, put a lock on it and leave it outside. If you have room for a giant hole you have room for a chest freezer.

GL

Uhhh, yeah. No not so much. The place on the shaded north side of the house where there is room for a 24" square hole (not giant in my books) is on dirt and has no power. I guess because you would rather solve those problems than design a passive solution. That is OK. I would not.

Here is the deal. I'd like to return to homebrewing. I left because my beers had off flavors from high ferm temps. I have learned this and learned the solutions, all provided in this forum. BUT, I have no room or desire to acquire thousands of $$ worth of equipment that suck power and break down/need maintenence sooner or later.

My concept of an underground chamber to cool the fermenter could solve all my problems. If the experiment does not work, I can take it out and fill the hole. But it will cost me next to nothing to try it out.

My kingdom for a bomb shelter!

 

[starman]

You can get a poly resin sanitary ejector pit or sump pit (just not predrilled) for about $50-75. Those are typically 18"-24" diameter. (Check your carboys, buckets, or demis size first.) They come with lids, which in your climate, i would insulate. The heat gain would be a bigger problem than condensation, which wouldnt really impact a fermenter with an airlock.

With a little luck you might find a landscaping or electrical contractor with a big enough round auger wthat could knock out an array in no time. Well, unless youre on rockbed ... then you might want to rethink digging anything.

Geothermal cooling has been kicking around for ages. The cheap cost of energy in the US just made people forget.

 

[jaz5833]

Bury a Hi/Lo thermometer - the ones that record the highest temp and the lowest temp on the same mercury tube - for a week during the heat of summer and see what you get prior to going through the trouble.

 

[Hermit]

Living in SoCal a basement is not an option.

Why? If it is a matter of shallow bedrock, then I can MAYBE understand why this would work. If it is other reasons you will be trying to solve what the experts have given up on.

 

[zepolmot]

Having lived in San Diego for the past 27 years and having quite frequently dug in the ground around my house during the summer months my guess is that unless you dig at least 6 feet down, you're not going to get much cooling effect.

This was exactly my concern. Also, if the chamber is going to be just the right size for the fermenter you may run into the issue that you're actually trapping the heat caused by fermentation. This is pretty interesting, keep us updated.

 

[Komodo]

Seems like people have already solved this with the cheap 2" foamboard fermentation chambers, frozen 2 liter pop bottles, fan, etc. It's a little work, but great reults. Please don't get me wrong, I'd be one of the first to dig a hole for fermenting! I'm also pretty damn sure that I've never once walked into my hardware store and bought something for it's intended usage. I cringe when they come to "help" me and ask what I'm doing, and if I give any intel their eyes glaze over. LOL

 

[brewingmeister]

Really interested to see what comes of this. The possibilities are nearly endless. What size are going for? The material cost will likely be way more than a used fridge but it will be unique at least.

If you are just trying to put one carboy in it maybe a tall cylindrical trash can would be cheap and effective. Plastic so it would be glass safe and tall enough to not collect water. I guess it all depends on the temp the ground holds....get digging.

 

[BrewProject]

i haven't posted in quite some time, in fact, i haven't brewed for a couple of years.

this thread got me interested when i found it because a buddy and i are in a similar situation.

country cabin, off the grid. solar and wind power only and mostly DC power. the only way i could think to prolong the outdoor brewing season (if fermenting outside) was to do something like this thread mentioned.

i talked ago about digging down 6-8 feet to my buddy i used to brew with. we travel to this country cabin on weekends a lot. we meet the owner out there and he has been wanting to brew, but does not have the power resources to do it.

my plan was to go about 8 feet deep, 2 ft x 2 ft. i would stack cinder blocks in the bottom to help with flooding that would surely occur (at least through seepage). 2 cinder blocks deep with a 3/4 treated piece of plywood on top of the cinder blocks for holding a primary and secondary, along with some boxes of bottled beer.

my plan was to line the walls with lattice, so that it helps prevent cave-in, but allows the hole to breath.

my plan was also to cover the hole with a 4' x 4' piece of plywood, thus forcing all water down into the ground a full 1 foot away from the hole in every direction. i kinda like the elevated covered opening now that i read it in this thread. maybe a combo of the two ideas would work best.

anyway, i don't think it will allow for year round fermenting, but it would probably greatly extend it... perhaps making a 6-8 month outdoor brewing season possible...

any thoughts?

thanks

 

[starsailor]

I am thinking about 6" cinder blocks for the walls (no rats!), then finish them off with spray on bedliner. :cross:

Only do this if you've got pretty dry high ground in your yard. If it's a low area or holds water and doesn't drain quickly during heavy rains you're building a pool. As with any underground concrete structure, it's best to waterproof the outside of the wall not the inside. You can use the cheap asphalt based roll-on waterproofing on the outside of the wall and protect that with a sheet of poly or styrofoam. This would all be way less cost than spray on bedliner.

Also, as others have suggested, dig 6-12" deeper than needed and put some gravel under the floor for drainage. It might be a good idea to slope the floor a little to the center and put a drain at the low spot. A drain would also make cleaning up any blowoff or spillage a whole lot easier. An easy way to do this would be to line the bottom with a sheet of styrofoam insulation panel (the pink stuff at HD or similar) over the gravel and pour a couple of inches of readimix concrete on top of it with a cheap PVC shower drain bedded in the concrete to form the drain. Use the concrete to make a 1/8" slope per foot. Oh, and don't forget to cut a hole in the styrofoam where drain goes. Don't ask me how I know that.

 

[LowNotes]

If you are in a hot and dry climate, you can also probably get a couple degrees of cooling using some kind of "swamp cooler". Wrap the fermenter in a wet/damp towel and the evaporation will draw heat out from the fermenter. Again this really works best the drier the climate is, but it is a tried and true passive cooling solution. (and cheap too)

 

[jaz5833]

Growing up in central VA, my dad had a "well house" that basically was an enclosure to house the well and its pump. It was an 8x8 block wall room 6 feet tall that was roughly 5 feet underground and the remainder above (picture a tornado cellar with a small peaked wood house on top for storage). It was lined with shelves for storing potatos and such and rarely got out of the mid-50s summer or winter. The floor was about 6" of 3/4 gravel and water was never an issue.

It would have been a perfect place for brewing.