Fermentation temps & aging

[RoatanBill]

FYI - I have no brewing experience or equipment - yet. I believe I know what equipment I want for the hot side and now need to figure out the cool side.

Ambient air and tap water temperature where I live is a minimum average of 85 year round. I intend to keg everything. I intend to ferment in carboys or SS vessels, but not conicals. I have an 8'x8' walk-in refrigerator available for this project initially, but will have to give that up after a few months.

If I want to brew numerous different recipes (ales & lagers) one right after the other, what should the cooling environment consist of? Stated differently, for maximum fermentation and aging flexibility, what should I build or purchase to properly ferment and age a dozen different beers simultaneously as though I had a brewpub?

I'm trying to wrap my head around how to go about supporting 3, 6, 9, 12 fermentation temperatures the way a real craft brewer would do it. I have an idea how to go about it, but I don't want to reinvent the wheel.

 

[Yooper]

Even pro brewers don't use 12 different fermentation temperatures. Without a glycol jacketed conical, you can still easily maintain optimum temperatures.

Most ale yeast strains are best at 65-68 degrees (fermentation temperature, which can be 5-10 degrees higher than ambient depending on activity), and most lager strains are best right around 50 degrees.

Lagering (cold storage) is done as close to freezing as possible, like 34 degrees, but some will go a a bit warmer (40 degrees) for speed. Beer ages fastest at warmer temperatures so it's a compromise between flavor and time.

The easiest way to do it is with a fermentation temperature. A small chest freezer or fridge, with a digital johnson controller. You can dial it to your desired temperature, say, 64 degrees for this yeast strain, and it will maintain that temperature. You can dial it up for a diacetyl rest, or when fermentation slows and you want to increase the temperature a couple of degrees, then dial it down for cold crashing.

 

[RoatanBill]

Yooper:

I used 12 only as an example as I have no idea how many brews I might want to have going at the same time. I'm trying to solve the problem of just 2 fermentation temperatures. Solving for 6, 12 or more is just applying the solution over and over again.

On another thread on this site, the following was posted by friarsmith:
"6-8 days at the desired fermentation temp, 3-4 days a few degrees warmer so the beer fully ferments and burns off fermentation byproducts (a good time to dry hop too), then 5-8 days cold crash around 35-45 degrees"
That's 3 different temperatures for a single beer and having 2, 3 or even 4 different beers going simultaneously isn't that far fetched.

Since heat is free here, if I need any I'll just expose the fermentation vessel to ambient air. For cooling I've considered using an insulated box (old broken chest freezer, purpose built box, whatever) with separate insulated compartments within it. Per compartment use either a glycol supply or Peltier modules to maintain that compartments temp independently of its neighboring compartments temp using electronics to monitor and control.

That's my idea, but I don't know how other people have handled this problem. Folks in the craft brewery business must have devised a solution and I'm trying to determine what experience has dictated for them.

 

[Yooper]

"6-8 days at the desired fermentation temp, 3-4 days a few degrees warmer so the beer fully ferments and burns off fermentation byproducts (a good time to dry hop too), then 5-8 days cold crash around 35-45 degrees"
That's 3 different temperatures for a single beer and having 2, 3 or even 4 different beers going simultaneously isn't that far fetched.

Wow- that is 3 different temperatures for a single beer.

However..........I keep fermentation temperatures at the optimum temperature (most ale yeast are pretty darn close in those temperatures, so you could do 2 or 5 or whatever at the same time), and then near the end of fermentation let the temperature rise a bit. It doesn't have to be xxx number of degrees- it can be 2 degrees, or 5 , or whatever. Or no rise at all for most yeast strains.

I don't cold crash before packaging, since the beer is being kegged and put into the kegerator anyway.

You won't want your beer storage/fridge to be the same as your fermentation temperature anyway, so you really don't need something different. It can go in the kegerator or beer fridge if you want to cold crash (and lots of us don't).

I'm a perfectionist, but I still don't require three different temperature zones for a single ale during fermentation. That's crazy.

 

[BWE]

FYI - I have no brewing experience or equipment - yet. I believe I know what equipment I want for the hot side and now need to figure out the cool side.

Ambient air and tap water temperature where I live is a minimum average of 85 year round. I intend to keg everything. I intend to ferment in carboys or SS vessels, but not conicals. I have an 8'x8' walk-in refrigerator available for this project initially, but will have to give that up after a few months.

If I want to brew numerous different recipes (ales & lagers) one right after the other, what should the cooling environment consist of? Stated differently, for maximum fermentation and aging flexibility, what should I build or purchase to properly ferment and age a dozen different beers simultaneously as though I had a brewpub?

I'm trying to wrap my head around how to go about supporting 3, 6, 9, 12 fermentation temperatures the way a real craft brewer would do it. I have an idea how to go about it, but I don't want to reinvent the wheel.

To be honest, I believe you may be trying to hard to fast. I don't know what your experience with brewing is, but if you have no equipment I will assume minimal.

That being said, I would start with an ale to get your feet wet. As long as you cool the wort down to around 68 before pitching, you can actually just leave the beer in a room... IF you have your house at around 70 air conditioned. It will turn out just fine. I've made LOTS of excellent tasting beers by fermenting at room temperature.

Yes, if your wanting to start off with a Lager, you'll have to have a fermentation controlled setup that can get you anywhere from 35-65°F. As far as cold crashing... Just use your keezer,Kegarator, fridge, or whatever you may have to serve out of.

But if your looking at large scale production for a brew pub.... probably need to go with pro grade equipment.

 

[RoatanBill]

Yooper & BWE: I spent 30+ years in the DFW area before moving to the Caribbean.

Yooper:
I too am a perfectionist (Engineer / Software Developer). That's why I asked for some insight into this issue. I have to allocate floor space for the hot side, the cool side (Fermentation) and the cold side(keezer) somewhere at the wife's bakery. Therefore I have to guestimate what all the equipment looks like.

The cold side is easy with the 8'x8' walk-in available at least during initial experimentation. Once I get brewing the cold side will become self evident and I'll get / build whatever it is I need. The cool side is more involved with differing temperatures (ale vs lager) and varying hold times. I have no temporary equipment for that purpose so I need to construct something and that means knowing what to build.

BWE:

Due to my background, I don't function well on incomplete information, so I ask lots of questions that knowledgeable people can dismiss or minimize precisely because they are knowledgeable. I'm beer ignorant but learning. Trying too hard and too fast is part of my being; It's the way I was educated.

I did intend to start with ale because I normally drink Guinness Foreign Extra. As mentioned above, this is going into the wife's bakery and the space available is not air conditioned (85-95+ degrees) so I have to come up with something. I'm trying to figure out what with enough flexibility that I don't discover I built the wrong thing.

BTW - I mentioned the brewpub only as an example to highlight the issue of multiple beer styles with various fermentation requirements and times and they all need a physical controlled environment as the worst case. Engineers always plan for worst case.

I wish a brewpub / craft brewer business person would pipe in as they MUST have solved the problem.

 

[Yooper]

I wish a brewpub / craft brewer business person would pipe in as they MUST have solved the problem.

They certainly have solved the problem, based on their needs.

One of my friends has a brewery in S. Texas- he has glycol jacketed fermenters outside.

Another one of my friends has a brewery in Milwaukee- he has ales at 66-68 degrees, and lagers fermenting at 50 degrees. He has one huge room for ales and one medium size room for lagers.

The bright tanks are also serving tanks. So they are cold- about 40 degrees. They can lager in there if they want, before they serve.

Glycol jacketed fermenters are typical, but not required if a cool room is available, however since the fermenters are at least 25 feet tall in many breweries they tend to have glycol jacketed fermenters.

For smaller batches or smaller breweries, they will be in a walk-in cooler.

 

[BWE]

I would suggest (off of what it seems your asking) TWO large deep freezes that you can put an external temp controller onto. The Inkbird is a great product. You could have one for Ales and One for Lagers. This would give you two very consistent temperature controlled fermentation chambers to ferment in and you can shove a lot of buckets/carboys, or whatever you desire into it.

As far as stepping up your temps, you would either have to do all your beers at the same time in the temp controlled freezer, OR remove them one at a time into a separate smaller Controlled Environment (smaller fridge possibly, also controlled with an external controller).

As far as "Typical" ales go... pitch at 68°F and forget about it. If you like you could bring it up to 72ish after day 3-4 if desired, but it's not absolutely necessary. Lagers tend to need a diacetyl rest after 10+ days at 65°F.

The cold crashing can be done in whatever your serving out of.... A Keezer possibly?? Look up ideas on here or on google. Thousands of ideas.

This is a great place for questions and there are a lot of helpful people on here. But what you'll find is... You must learn your own methods and there WILL be trial and error, and you WILL have failed batches. That's not to say that you can't learn from others mistakes. But everyone's situation is different. As Yooper stated, problems are solved based on needs. Continue to ask away though. You'll be putting out good batches in no time.

 

[hottpeper13]

What I would do in your situation is buy 3 ST1000 controllers and heat mats(not the strips) and a roll of Refelctex insulation. Now make a cover that you can slid off over the top of the carboy. Tape the heat mat around it and put the sensor where the mat isn't and slide the cover on. Put this in your walk in and set the controller to about 3*f below what you want and then moniter it. Eventually you will know were to set for the ambient temp of your walkin. When you loose the walkin you will have the stuff to do the same thing in a chest freezer you just need to control the freezer with a separate controller.

 

[RoatanBill]

Yooper:
Whole climate controlled rooms or dedicated walk-in refrigerators are obvious solutions for folks with "needs" large enough to afford the expenditures. I should have guessed that the big guys would go that route. I knew of the jacketed fermenters, but are not something I want to get involved with given the comparatively puny volumes I'm considering. Too many parts to clean.
From your description, the pros must also consider multiple fermentation temperatures a bit extreme as multiple temperatures in a given enclosure isn't really feasible. That tells me that having the ability to control individual batches isn't really that important after all.
"Bright tank" - What the .... Thanks for cluing me into another gadget I was unaware of.

BWE:
From this dialog, I've concluded that I only need to worry about 2 temperature ranges. Other posts on this site were giving me the impression that each recipe had a special temperature. I've read posts where people were moving things 1 or 2 degrees and correlating a positive effect they experienced to the change. Maybe that's true and maybe it isn't. I have to wonder how they managed to keep all the other variables nailed down exactly between experiments.
Having 2 chest freezers sounds like a reasonable solution and with identifiable floor space foot prints.

hottpeper13:
The walk-in I have access to is temporary as the wife will want it back for her own experiments (dough, pastry, creams, etc). Therefore I don't want to invest in equipment that will become obsolete in short order. Besides, electricity costs 3 times as much here as in the US. Paying to cool the box and then putting a heater inside goes against my grain and hurts my wallet.
For the eventual permanent solution, I'll go with two insulated boxes and variable temp controllers.

Thanks guys.

 

[BWE]

BWE:
From this dialog, I've concluded that I only need to worry about 2 temperature ranges. Other posts on this site were giving me the impression that each recipe had a special temperature. I've read posts where people were moving things 1 or 2 degrees and correlating a positive effect they experienced to the change. Maybe that's true and maybe it isn't. I have to wonder how they managed to keep all the other variables nailed down exactly between experiments.
Having 2 chest freezers sounds like a reasonable solution and with identifiable floor space foot prints.

You will find 1000 different ways that 1000 different people do differently from each other. You may have a brew that you like better fermented at higher temps. Or one that keeps cool the whole time. Each situation is unique. But the typical fermentation temps are a great place to begin. When you start attempting repeat-ability in your beers (which is tough) then you'll want to keep temps within 1° or tighter. I hope we have helped. Stay on the sight and stay diligent. There is endless information here. And people do crazy off the wall things to experiment. Some work, some don't. All part of the hobby.

 

[RoatanBill]

BWE:
I get what you're saying. Brewing is science plus art. As an engineer, I keep leaning towards perfecting the environment conducive to the science and pay no attention to the art as I have NO experience with it.

When you mentioned "crazy off the wall" things people dream up, I definitely fall into that category. What I've got planned for the hot side I'll bet no one has done before. Don't ask. I'll video anything I do, and if it works, I'll put it up on YouTube. From these posts my mind conjured up a fermentation section also fairly unique. Everything involves automation and control - the science side. I'll learn about the art side once the environment is available to me.

Thanks much.

 

[Morrey]

Look at SSBrewtech's glycol chiller. It has four ports that can all run individually to cooling coils in 4 different fermenters if you choose. If each fermenter had it's own controller, it powers on or shuts off the cooling supply as demanded. From that regard, you could build a glycol chiller and run as many units as you choose with pumps to each fermenter from the chiller's reservoir. Sounds complicated but actually easy to do.

I have two big freezers with temp controllers. I also have a big refrigerator with a temp controller. Inkbird ATCs are $30 each, old freezers are $100 on Craigslist. I saw a scratch and dent 14CF freezer brand new at HD for $300 just last week.

In the long and short of things, I usually run fermenters at 67F for most ales, 50F for most lagers, and 34F for lagering/conditioning/carbing. I was thinking like you at first that each beer needed a specialty temp and I damn near drove myself nuts worrying about it. Many brews later, I just let 'er rip at the temps mentioned. Yeah, there may be a specialty temp variation here and there, but I quit fretting over that too. I will admit that distillers washes need to be 85F-90F, so when those happen, that ties up a fermenter but only takes 5 days.

 

[RoatanBill]

Morrey:

I've seen the Brewtech gadget. It's OK, if you have a jacketed fermenter or some way to route the cooling water over, in, around or through the fermentation vessel. With a carboy I'm not keen on inserting a heat exchanger through the neck sticking into the beer or putting some kind of necessarily flexible jacket around it; that's too cumbersome for me. It offers no real solution to cooling wort from a kettle. What they're really offering is the monitoring and control along with the cooling under certain circumstances.

I'd also want a much larger cold well and better insulation, bottom, sides AND TOP. Electricity here is damned expensive so efficiency is always a concern. If I invested in a chiller, it would have to have the power to cool 20 G of 100 degree wort down to pitching temperature via a counterflow heat exchanger and that would require larger plumbing and more powerful pumping. I've got a way to get hot wort to about 100 degrees via a water storage tank I already own. As I plan on heavily investing in automation, I'll provide my own monitoring and control.

 

[SanPancho]

FYI - I have no brewing experience or equipment - yet. I believe I know what equipment I want for the hot side and now need to figure out the cool side.

Ambient air and tap water temperature where I live is a minimum average of 85 year round. I intend to keg everything. I intend to ferment in carboys or SS vessels, but not conicals. I have an 8'x8' walk-in refrigerator available for this project initially, but will have to give that up after a few months.

If I want to brew numerous different recipes (ales & lagers) one right after the other, what should the cooling environment consist of? Stated differently, for maximum fermentation and aging flexibility, what should I build or purchase to properly ferment and age a dozen different beers simultaneously as though I had a brewpub?

I'm trying to wrap my head around how to go about supporting 3, 6, 9, 12 fermentation temperatures the way a real craft brewer would do it. I have an idea how to go about it, but I don't want to reinvent the wheel.

how big are these batches? thats the deciding factor here.

 

[RoatanBill]

SanPancho:
The minimum I'm considering are kettles of 20, 20, 20 but more and more I'm leaning towards 20, 20, 30BK. I'm using the suggestions from the Blichmann web site for kettle sizes to brew 15 to 20 gallons per batch with the possibility of doing a 10G batch.

 

[SanPancho]

well, that's gonna be a bit of a problem. how about 10g batches?

if you wanted to do a DIY system, you could make your own glycol chiller- basically you hack a big AC unit and put the coils in a large insulated tank, a ice chest works great for this. then you pump glycol to each fermenter as needed, you can use cheap inkbird/ITC controllers to keep costs down.

you could use a keg as a fermenter, and you just put it into a slightly larger vessel- either one you find or one you build. the gap between the keg and vessel wall is your cooling jacket. solenoids turn the flow off and on per temp controllers. or use larger vessels if you can find them. the point is, you'll be mimicking the jacketed fermenters we use professionally. super DIY.

individual temp control, fairly easy to find parts. MUCH better heat transfer than just using air. and if you do the research i think you can use saline water instead of glycol, which is pricey. and this can be scaled pretty easily.

but the fermenter size is whats gonna limit you. kegs are easy, but you'll likely only get about 10g out of one. nice thing about kegs is you can lift one out of its chiller tank to sample, clean, empty, etc. larger vessels might not be so easy.

pvc manifold to run your glycol to each vessel, with some insulation. easy to copy a pro setup. needs a big chiller, one big pump, solenoids, and temp controllers. only the first two really draw any amps, solenoids and controllers are negligible. probly very similar to the energy required by the walkin since air is so much less efficient at heat transfer than water.

 

[RoatanBill]

SanPancho:

Larger batches aren't an issue for me since I have access to lots of ice, existing freezers, a walk-in cooler and other refrigerators. I can "borrow" some ice or cool down one or two 30G plastic pails of water to 38F (that's where my wife keeps her walk-in). A chiller isn't absolutely necessary for me, but I'll probably get or build one just for convenience.

The only fermentation vessels I'm considering at the moment are glass or plastic carboys, some form of SS vessel that isn't a conical, and kegs. Kegs in particular have a lot to offer especially since there's a thread on this site that describes using kegs as fermenters and then transferring the beer to another keg all without ever exposing the beer to air using CO2 to push from one container to the other. I've got two 125CuFt CO2 cylinders that I use for welding, so I have plenty of gas. Because they're tall relative to carboys, kegs take up the least floor space and there's no danger of glass breakage. Floor space estimates for fermentation was something I needed to finish my design.

I started this thread to try to figure out how people handle multiple fermentation temperatures concurrently. I've concluded that I need 2 insulated fermentation boxes, one for ale and one for lager so each is in a specific temperature zone. Per box, if I want to, I could fine tune temps by subdividing the box via insulated interior walls and treat each sub unit as a discrete refer in itself. Since I have no access to Craigslist or other sources of cheap or used boxes, I'll have to build something. I'll just build it keeping in mind I may want to modify it

 

[SanPancho]

well if you want to just have one ale temp and one lager temp, its definitely doable, which we've already established here. the issue is obviously the individual adjustments +/-5 or whatever. which again, we've established is possible in various methods.

but to be honest, im not really sure "subdividing the box" is going to work very well. i assume that it would require another form of cooling, or at least individual fans to move the air to each box, temp controllers, etc.

my impression is that you're going to do just as much building and designing using air cooling as you would be with glycol/saline. and as noted above, air is much less efficient that water, which is a bummer if you're the one paying the bills. if you're convinced that air is what you have to do, then so be it.

but you will need to crash. and thats going to require you to have the ability to cool individual fermenters down to about 35F, or you'll have to cool everything at once- which means your fastest beer has to wait for your slowest beer before you can crash everything down together.

less than ideal, but if that's the road that seems most realistic/plausible/do-able then you gonna have to just make it work.

in that case, you really need to sit down and plot out a brewing calendar. the more beers you can brew in one day the more likely they are to be finishing around the same time (all ales, or all lagers). which means you wont have to have such a wide variation of temps at one time. i dont think yooper really understood you when she said 12 temps at one time is crazy. one beer could be fresh in the tank, another needs to finish warmer, another in d-rest, a saison is at 80, ale at 70, kolsch at 62, lager at 55, somebody is crashing, another is holding for dry hop, etc. etc.

the problem there is that some beers will sell faster than others, and you dont know until you start serving them. in a pro brewery with a brewpub, you typically will have a few fermenters of X barrels, and then a few of 2X capacity. that way you make a double batch of your best sellers, then single batches of the stuff that goes more slowly, seasonals, experimentals, etc. or you can split the double batches - one regular ale, one with extra dry hop, one saison and one with fruit, try different dry hops for same base beer, etc. etc.

maybe you should do those calcs first before you build anything. without true individual temp control you're gonna have alot of scheduling to do. it can truly become a nightmare. research the styles you want to brew and put timelines together for each. then start crunching numbers on the calendar.

 

[RoatanBill]

SanPancho:
I mentioned "brewpub" to provide a framework for my thinking that others would readily understand. I have no plans to start a brewpub, have no space for the storage requirements it would entail, and since I have NO brewing experience at present would be foolish to contemplate.

However, the fermentation issues a brewpub has are simply the magnification of the issues an individual brewer has and is why I mentioned the term. For the present I want to become an individual brewing beer for my own consumption and possibly for a few friends. I do want to purchase or build infrastructure that won't limit my future options.

Since my research has identified fermentation as THE critical link in the beer chain, I want to PLAN on having a fermentation environment that I won't curse. On the island, my only concern is with cooling as AVERAGE ambient is way above fermentation temps year round.

Your post seems to agree that having the ability to make adjustments per batch is of value. I think neither you or Yooper is right or wrong, just setting the bar at different heights. I have no idea where I'll set my bar, but the engineer in me will design / build for worst case as best as I can determine it. That's why I started the thread.

The most likely fermentation vessel I'll use is a keg @ 80% capacity. I see no way to use anything but air flow as the cooling medium just as airflow is used in a home refrigerator. The metal body should aid in heat transfer. A small muffin fan moving air only when cooling is to be applied to the keg(s) in a particular cell of the overall fermentation box is a given. What produces the cold air will likely be a moving cold liquid pumped through a copper coil inside the cell. Electronics will monitor and control valve actuation. The cold well upon which to draw from will likely be a chiller eventually, but I could use iced water in an insulated container during testing and experimentation.

For example, If I arbitrarily decide to brew either 8 or 16 gallons of beer per batch, that would occupy either 2 or 4 kegs. If I made each cell appropriate for holding 2 kegs, I would use up 1 or 2 cells in the fermentation box, each with its own monitoring and control capability. Arduino Mega's are cheap and support dozens of inputs and outputs.

The fermentation box could be a welded up aluminum / mild steel / stainless steel frame using prepreg sheets, fiberglass and epoxy and a closed cell foam produced as needed from chemical components. I've worked with these materials in the past.

 

[SanPancho]

got it. ok, i had thought you intended to provide beer for the island. in that case what you're proposing sounds totally reasonable. its still a ton of work, and my initial impression is that you're gonna actually make more work for yourself, and have a less efficient system.

you're already using water or saline as your cooling medium, why not just go all the way? get plastic beer tubs for your kegs, wrap them in insulation. add inlet, outlet, solenoid, done.

if you're already moving the cold liquid to each chamber, why bother switching mediums? yes metal helps the transfer, but liquid to metal is still superior vs air to metal in terms of efficiency.

i dont mean to be argumentative, but i just dont understand why you'd set up a cold source with a water/saline medium, plumb it to each cooling chamber, and then switch to air at the last minute. water will give you faster heat transfer and better temp maintenance, with more thermal mass.

so again, not trying to argue, it just seems to me like what you describe above is so close to a full glycol type system it seems odd, and more work, to switch to air at the last minute.

 

[RoatanBill]

I thought about setting the kegs in a water bath, but rust worries me. Stainless in constant contact with air and water will rust given the slightest scratch in the chromium oxide layer that is what makes stainless stainless.

I wouldn't use salt (definitely will corrode SS), but would consider auto antifreeze or glycol. I use glycol in my TIG water cooler.

This is the external portion of the keg so it has no influence on the beer. Auto antifreeze has corrosion inhibitors so that may work; I just don't know. Air is safe from the rust perspective and given that a standard kitchen fridge uses air to successfully cool the entire fridge contents, I know air will do the job given the proper air circulation. If I throw in some desiccant pellets, I can reduce the humidity in a sealed chamber too.

The attached is the (unfinished) CAD drawing I'm working on for modular fermentation chambers that can be stacked on a shelf next to one another. The exterior dimensions are 13Wx21Dx29H and holds 2 5G corny kegs. The insulation layer is 1" all around (top, bottom and sides) but I could make it anything I want.

The interior could easily be made water tight by using fiberglass layups. The green thing is an air/water heat exchanger of 6 3/8" tubes and the red horizontal tubes represent 1/2" water input and output. There's a 40mm fan pushing air across the tubes inside a 2" square tube. The blue tubes are for blow off hoses. I haven't put in a penetration for electrical yet and I could put a tiny pump in there also.

I'm just thinking about it at this stage. I should also mention that this gadget will go into non A/C space that regularly sees 85 to 105 degrees. That's why I may need 2" foam.

 

[SanPancho]

most glycol does have rust inhibitors, so thats not really an issue. and you will see rust in a walk in cooler just as easy as you see it in a glycol system. the oxide layer on exterior will be fine, you gotta really abuse it to generate rust. and it will regenerate on its own just with normal atmospheric conditions. by the time one of your kegs gets a rust problem, you'll have gotten plenty of use out of it.

given your typical ambient, i'd say 2" is the minimum. go crazy with it. you're gonna need it.

i just realized one other issue you will have- extended aging. not sure if you're doing any beers with long aging times, but that's gonna be tricky with those ambient temps. although it could work pretty well for some wild stuff like sours.

 

[RoatanBill]

I did consider just peeing chilled fluid on to the sides of the kegs and allowing gravity to put the spent fluid back into a reservoir. It's the thought of rust that halted that direction. I may revisit the issue. As you say, at the price of these things, it's not the end of the world if it gets too gross to use in a few years.

All the commercial freezers we've purchased are all 2" closed cell foam insulation and we've got some at minus 10 that sip electricity. A few clicks on the CAD program and I can have 2" insulation.

Extended aging was another reason for wanting a robust fermentation environment. It's what also led me to the module design I showed. Instead of some box of a given dimension and capacity, the individual modules would allow me to weld up a shelf, possibly several levels high and just stack the modules on it. It's expandable as needs dictate as long as I develop the patterns and gigs to produce more when I need to.

It's not knowing what I'm going to do, what recipes I'm going to like and what schedule I'm going to brew on that keeps me looking for the most flexibility during this thinking and design stage. If I was an old hand at this, things would be a lot easier. I'm just trying to avoid missteps but in the process will do extra work simply because it might be a good idea down the road. Given the temps here I have to have something for fermentation so a half dozen of these modules should give me quite a bit of capacity to ferment , age and experiment.

Thanks for your input.