Update on the BrewJacket Immersion Pro

In March of 2016 I wrote a post, BrewJacket Immersion Pro Fermentation Temp Control, that was sort of an ad for a Kickstarter campaign. It felt a bit scuzzy of me at the time but I felt it was my best hope at getting started in homebrewing if good fermentation temperature control was considered paramount; I believe it is. It turns out I was correct on the “my best hope” business.

The original BrewJacket had been around for a couple of years but was a cooling only device. The Kickstarter campaign was for a redesign of the circuitry so that it heated and cooled. It succeeded. I went with the No Wait Carboy level which got me a then current (cooling only) model BrewJacket immediately and the updated electronics several months later when they were ready.

This year when I was finally ready to begin brewing I swapped out the electronics and started looking at the instructions closely. BrewJacket wisely suggests running a test with just water in a carboy to get a feel for the system before committing it to your first batch. I did it and it ran great for about an hour and then quit. No lights or anything, although I did smell a faint burnt plastic odor. I reached out to BrewJacket and they (and I) assumed it was the head unit. They sent me a refurbished one within a few days. Swapping out the heads meant no change whatsoever though. Then I took a closer look at the external power supply and noticed a small, warped, bubbled area on its bottom. I contacted them again and they sent me another power supply. Eventually everything was working so I ran the test. Put me a couple weeks behind for my first brew but whatever. I am stoked I have done 3 batches already!

Everything was good until it wasn’t. I was using a Big Mouth Bubbler 5-gal carboy with spigot. I had left water in it for a couple days and absolutely no leaks. A day after I put it into the BrewJacket insulating bag it leaked and trashed the bag. The bag got a strange white mold all over where it had been wet. A fairly quick drying in our low humidity environment and a couple cleanings and it seems to be OK. I now only use those spigoted carboys as bottling buckets!

I brewed my first batch of beer on 2 July of this year, the second on 18 July, and the third on 8 August, which is still in the fermenter. So far the Immersion Pro is working like a champ. But there are some limitations. I will lay out some pros and cons as I see them, so far, though some are specific to similar circumstances as mine. [Addressed somewhat in that first post, with some update coming.]

Pros and Cons

Pros

  • Can be adjusted from +/- 30°F from ambient temperature
  • Maintains ~+/- 0.2°F from where set
  • Cooling 10°F takes approximately 12 hours [@ ~74-82°F ambient temp]

Cons

  • Can only be adjusted from +/- 30°F from ambient temperature
  • No real cold crashing if ambient temp is much above fermentation temp
  • One batch at a time
  • Somewhat noisy
  • To do anything with the fermenting beer means pulling the ImmersionPro out
  • This needs two people: one for removal, one to do whatever: gravity reading, finings/gelatin, dry hopping, ….
  • Cooling 10°F takes approximately 12 hours [@ ~74-82°F ambient temp]
  • The ferrite rod itself can only be sanitized with iodine-based sanitizers, like Iodophor

The temperature range of this thing is pretty incredible, except when it isn’t. In July and August, it has been approximately 72-82°F+ [thermometer tops out at 80°F so “82” is max] ambient [a daily change] in the spare shower where the fermenter is residing. This means no actual cold crashing. The best you could obtain is 42-52°F and that would be seriously taxing it by running almost constantly without the true benefit you are looking for. The opposite would exist if you were trying to ferment warm in a very cold environment. It only gets down to about 60°F in the winter in that shower but I cannot brew then anyway, even though that would be awesome for doing lagers along with the Immersion Pro.

Entire unit showing drawstring closed around neck of carboy. 1st batch.

The head is somewhat noisy but it isn’t really an issue for us since it is in a spare bathroom off the “entertainment” room. In a small aprtment or sitting in your living room, like one of their images shows, it would probably be disturbing to many people.

Close up of krausen and rod in carboy. Normally the jacket would be closed tight. 1st batch.

Removing the carboy lid or only the Immersion Pro is a bit more complicated than a regular carboy lid and tube/airlock. I guess a sanitary place to lie it could be made if you had to do something inside the carboy by yourself but it seems mighty problematic. Not that I am a fan of the wife holding it up above while I do what I need to quickly but that’s “easy” at least.

Closer look at the head unit. 1st batch.

Part of the sanitation issue is that it requires an iodine-based sanitizer. I use StarSan otherwise. So I needed a special “vessel” to make up Iodophor and put the rod in which is not the smallest nor best shaped/weight for such things. Then there is the “air drying” that iodine-based sanitizers require. How the fuck is that supposed to happen with a rod? Well, with any shape really? There is no way to suspend it and if it touches anything (assuming something sanitary) then it cannot dry fully. This might be my biggest peeve about the whole thing right now.

Maybe I am missing something obvious about drying iodine-based sanitized items but this is inconvenient, to say the least. If you already primarily used iodine-based sani then you are golden. (And perhaps laughing at me. Oh well.)

View from the side showing blowoff tube and temp probe. 3rd batch.

As for temperature stability, it is usually +/ 0.2°F from your set point so a total fluctuation of 0.4°F. Sometimes, especially if changing several degrees it may fluctuate for a bit at +/-0.4°F until it settles in to temp. That is pretty rock solid in the stability department!

Head, lid, rod and high krausen. 3rd batch.

As for how quickly it can cool, it has mostly met my needs so far but I can imagine that I might have reason to cool faster (or further) than it can go. Again, a 10°F change, for me, at ~74-82°F ambient, takes a bit over an hour per degree.

Calming down. Things have gotten a bit gunkier. 3rd batch.

The unit uses a blowoff tube for ale primaries and a one-way check valve for lagers and ale secondary, if you like. I have only been using the blowoff tube so far and it has been working great, although I do wish it were slightly bigger as I can see it getting blocked someday. The supplied connectors and tubing are 3/8″.

The jacket I got is compatible with normal 5 and 6.5 gal carboys, Speidel 20 and 30L, Fermonster PET 6 and 7 gal, 5 and 6.5 gal plastic and glass Big Mouth Bubblers, and other PET carboys in this size range. The possible difference between any of them is simply which lid you use. Currently I use the Universal Big Mouth Bubbler lid with a plastic BMB 5 gal.

All in all, I really like my Immersion Pro as it was my ticket to “solving” fermentation temperature control, a big hangup for me. I am looking forward to moving on from certain of its restrictions if/when we can get more space cleared in the detached “garage” and get another refrigerator/freezer and dual-stage temp controller out there. I also need space for conditioning. So , ….

Oh, what a hobby.