The Fresh Loaf

A Community of Amateur Bakers and Artisan Bread Enthusiasts.

Anyone use a CoolBot?

bikeprof's picture
bikeprof

Anyone use a CoolBot?

I've been looking into coolers for a microbakery, and the prices and my space constraints are not making the options for commercial coolers look very attractive.  So I recently found this:

http://storeitcold.com/index.html

Basically a controller to make a window air conditioner cool a home-built cool room (inventor is apparently an organic farmer who was looking for solutions to keeping veggies cold).

Since I'm going to be either putting up new walls and insulating and finishing existing ones for my planned operation, this might be a decent option (but would love to hear your views)...Any experiences out there with the CoolBot? Opinions on the concept?

drogon's picture
drogon

It's a question I've often wondered - exactly what is a microbakery. My own thoughts is that it's one that you run from home without your own retail outlet - ie. you supply farmers markets, and other shops wholesale.

You're not looking at a walk-in fridge - that's full-on bakery size to me... I just have a domestic fridge and I use it for my overnight ryes and to store my starters in.

What's your plans?

-Gordon

bikeprof's picture
bikeprof

I share the same view as what a microbakery is, but you can still outpace what a domestic fridge can hold...I'd like to be able to retard 100 loaves at a time if I need to...ideally using covered bun racks

gerhard's picture
gerhard

talk to someone using this device in a real life setting.  I would be sceptical of claims and online testimonials.  Refrigeration contractors aren't dumb and if it was this easy why wouldn't they have this or something similar as an option.   

Gerhard

bikeprof's picture
bikeprof

;-)

Trevor J Wilson's picture
Trevor J Wilson

I worked in a bakery that just had a regular window-mount air conditioner installed into a small add-on room with insulated walls. The AC did the trick just fine -- we could usually get the room into the low 60's F (though during peak Summer heat it might only get down into the high 60's F). It couldn't fully retard the dough, but it was always good enough to slow proofing to manageable levels when days were hot. 

Additionally, we had it outfitted as a proofer, which was very helpful during our cold Vermont Winters. Of course, you couldn't use both proofer and cooler at the same time. Well, actually you could -- and we did by mistake, on occasion -- but as you can imagine that didn't work out too well.

Cheers!

Trevor

 

dabrownman's picture
dabrownman

of ice cream from 100 SF to 250,000 SF and it isn't easy to design a room that works efficiently and is fool proof.  A 36-42 F room is quite different than one that operates at 50-60 F or one made to run in the run in the 60's.  They all need to defrost and the lower the temperature the more time they need to defrost and the more times they need to defrost.  A wall air conditioner can keep a small room in the low 60's if you remember to shut it off a couple times a day for an hour or so so the coil can defrost in the summer but hte winter is worse since shutting it off won't defrost it when it is below freezing outside..  The humidity in the air condenses and freezes on the coil and has ti be removed.  

To hold a low temperature of 46-42 required a coil that is heated when it goes into defrost and a place for that water to go when it turns into liquid. Since the box is so cold just shutting of the coil won't get rid of the ice fast enough so it has to have some kind of mechanical device or method to do it. Refrigeration works by flashing the very cold liquid refrigerant coming from the compressor and condenser through a nozzle turning it into a gas which releases the cold in the liquid while blowing air through the now cold evaporating coil making the air being blown through the coil cold .  Then the now hot gas is returned to the compressor and condenser which turns it back into a liquid again and the cycle repeats.

The coil works on a 10 F temperature differential which means that the the air being blown through the coil that actually cools the room is 10 F lower than the air in the room.  So in a 38 F box the air being blown through the coil is 28 F which is 4 degrees below freezing and why the humidity in the air is taken out of it and freezes on the coil.  Eventually the coil gets blocked by ice building up on it so that no air can be blown through it to cool the room and why defrosting is a requirement for coolers as well as freezers when the air temp in the box is -10 F and the air being blown into it is -20 F.  Freezers require different coils and defrost mechanisms than coolers because of the extreme low temperatures.

No air conditioner is going to get any small room down to refrigeration temperatures of below 42 F. Getting below 60 F will likely freeze up the whole unit and blow it up eventually.  Real commercial coolers and freezers are designed with redundancy to make sure the box never goes above the set temperature.  We have to prove to the governing authorities through automatic temperature logging that the required temperatures are being met at all times or the food has to be tossed which could cost millions of dollars.  So what happens is that a system is designed to the job the then it is duplicated so that if any one piece is broken the backup can be either manually or automatically brought on line to maintain temperatures while the broken piece is fixed.  The equipment itself is super heavy duty and meant to run 24/7/365 for many years.

The boxes themselves are designed to maintain temperature for 48 hours even if the power went off and I had a mobile, electrical generating station on a tractor trailer ready to roll to any plant where the power was off.  The refrigeration electrical system was designed to hook up the 3 feeds from the generator to the switch box and all you had to do was throw the switch to get the power from the generator instead of the power grid.  Insurance rate reductions alone would pay for all of this redundancy in a few years. 

For a small home bakery it is better to get a few old refrigerators for cheap to do retarding in and put them on separate electrical circuits, or better yet, don't do any retarded loaves at all and lose a little sleep instead - sleep is free.  Anything mechanical or technology based is big potential problem for a small business if your business depends on it.

bikeprof's picture
bikeprof

and good to hear your analysis...which in turn suggests that there is quite an online conspiracy to make the CoolBot out as something that it can't be, based on the reviews, examples, and explanations I've read so far.

My conversation with Michel Suas at SFBI (based upon the scale I described for my project) also featured his recommendation to NOT rely on standard home refrigerators for retarding dough, as they are not designed to cool significant masses, as commercial units are (something your explanation tends to support too).  And that (when sufficient to the task) are a great tool for supporting a healthy and happy life as a baker, which includes sleep (and the latter points he was adamant about as well).  However, I imagine he would not be a fan of the CoolBot concept...and I'll keep looking for better empirical confirmation either way...

dabrownman's picture
dabrownman

no worries so I would get two A/C going one over the door and one at the opposite end.  Then you might be be ti get the temperature down and recover when the door is open in 24 hours.  The one outside will still freeze in the winter when the temperature is below 36 F but the one over the door and on the inside won't freeze up if you run at 38 -40 F for the set point.  It is more important to really insulate the floors ceiling and walls when dealing with low power inefficient cooling systems.  For an extra $400 bucks for a 2nd unit you might get something that would work for a small box. To get the recovery down to a little as possible you want to make sure that the box is full too.  Load it up with a bunch of scrap steel that will put off a lot of cold fast once the door closes.  Just the opposite of having thermal mass in an oven to out put a lot of heat fast after the door closes.

gerhard's picture
gerhard

with using window shakers for other purposes.  We have 2 Hilliard Chocolate enrobers and they have a tunnel on them that is cooled using a window air conditioner.  In the winter they will run all day with out complaint, our inside humidity tends to be between 30 and 40% in the winter.  In the summer our humidity is usually north of 70% even though we air condition to 20˚C and we can only run them for 1 1/2 to 2 hours before we need to run a defrost cycle, which is basically turning the compressor off while leaving the fan running.  The target temperature for the tunnel is around 12˚C and it can do that easily but I think if we wanted the tunnel to be at refrigerator temps (4˚C) we would have problems and the tunnel has many fewer cubic feet than even a modest room.  

If you are building a walk in cooler by adding cooling to just a room I would make sure it is well insulated to keep condensation from forming in the walls leading to mold issues.  The modular walk in coolers are well engineered and may cost a bit but are worth the investment since all the engineering has been done.

My 2 cents

Gerhard