Does anyone out there use one of these? I was thinking about getting one, but all that I see readily available have a heating surface diameter 4 or 5 inches less than my brew pot. I use a 5 1/2 gallon pot to do 3 gallon batches.
I have two induction tops. They are freaking fantastic to work with. Both of mine are 8.5"- regardless, it doesn’t have to be exact and can overhang. Weight might be an issue depending on glass surface or not.
A three gallon batch should be fine.
I may move in this direction ultimately but it’ll require a new induction capable kettle.
Have you tested the ones you have? It’s my understanding that if a magnet sticks to the bottom you’re good to go. A magnet sticks to both of mine, so I’d be okay if I get one.
Magnet test. Unfortunately, most of my nice ones are from the 80’s and despite being european fail the test. Hence my move towards some new equipment https://www.homebrewersassociation.org/forum/index.php?topic=18096.msg287804#msg287804.
I’m considering a 220v IB version that can handle 3k+ watts. Perhaps. 
The ones I have are both 110v 1800w so that’s about 6120 btu each. But since induction is so efficient 90% of the btu are utilized instead of 30-40% like a gas burner.
Normally I use a 20 gallon aluminum pot straddling two 9000 btu gas stove burners and have done 12+ gallon AG batches with it without issue. Except it takes more time and energy. I think the 220v IB could handle something like this 80qt.
I’m all for it too. Your 3 gal batches should be a snap.
The magnet test is not enough. Not all induction-ready stockpots are equal in their ability to heat using an induction range. The kettle that I built using an American-made Vollrath 77620 24-quart Tri-Ply stockpot heats faster without a jacket than the kettle that I built using a Chinese-made Vollrath 3506 27-quart Optio stockpot with a jacket. The Tri-Ply and Optio lines are both induction-ready.
With that said, do not expect aggressive boils from an 1800W induction range. I start with 4.5 to 5-gallons of wort and boil down to around 3.7 gallons. It takes two hours to boil 5 gallons down to 3.7 gallons.
Vollrath Tri-Ply 24-quart stockpot on an 1800W induction range
I have turned the stockpot shown above into a full-fledged boil kettle/mash tun
Now that’s what I’m talking about!
How do you feel about the performance? No aggressive boils but is it timely as far as reaching a boil?
I started out using an 1800w induction burner for my 2.5 gal BIAB batches. It worked well for heating the mash but getting 4 gallons of wort up to a good rolling boil was a struggle. I had to keep the kettle lid partially on to maintain the boil or it was just a good simmer.
I ended up poo pooing the 1800w for a 3500w and I’m much happier.
What make and model of stockpot are you using? An 1800W induction range should be able to bring 4 gallons of wort to a rolling boil without a cover. One does not need to achieve a heavy boil when boiling wort. Commercial brewers usually shoot for evaporation rates of less than or equal to 10% per hour.
In my humble opinion (and it’s just that), none of the currently available portable induction ranges approach the performance of a properly-sized propane stove. The 240VAC models are better than the 120VAC models, but they are still no match for a 60K BTU or better propane stove. The beauty of induction boiling is that it is quiet and much safer than propane when used indoors.
Its an 8 gal mega pot. Maybe its too wide but the 1800w burner just didn’t cut it. I’m very happy with the 3500w burner. I always read maintain a good rolling boil?
Great info! A total refit of my brewery? ??? Probably 2 new kettles or a big one and a 3kw model. or there are other options.
Boil-wise it’s more of a hard simmer that one is looking for AFAIK.
That’s a less than spectacular pot from an induction point of view. The Vollrath Optio line is basically the same construction. The difference in performance between a made in China Vollrath Optio stockpot and a made in the U.S.A. Vollrath Tri-Ply stockpot is noticeable.
The thing that I have noticed about the Chinese induction-ready stockpots is that they sing and/or buzz at a high frequency when used on an induction range. That’s due to less than complete bonding between the layers in the bottom. My children would squawk about a high-pitched ringing sound when I used the Chinese-made Vollrath stockpot. I could hear a lower-pitched singing sound until the stockpot heated up and expanded, but they said that it was like listening to a loud mosquito. The Vollrath Tri-Ply sounds like it has been placed on a gas range when placed atop an induction range.
Most home brewers boil too aggressively (I am guilty too). The generally accepted evaporation rate is six to ten percent per hour. Six to ten percent per hour on a 4-gallon boil is 0.24 to 0.4 gallons per hour. I was averaging roughly 0.65 gallons per hour on my induction range, which was an evaporation rate of roughly 14% when spread over the entire boil. If you are boiling down to 2.5 gallons from 4 gallons in a hour, then your evaporation rate is 37.5%.
https://byo.com/hops/item/2816-better-boils-adding-body-mr-wizard
[quote]As a very general rule, it takes anywhere from 60–90 minutes of boiling accompanied by 6–10% reduction in wort volume to accomplish the basic goals of wort boiling. Evaporation rate is really an indicator of the fact that the wort indeed boiled as expected and is also an indicator of how much DMS removal occurred during the boil. The removal of DMS has really become the single largest topic about boiling because DMS is such a distinctive and potentially objectionable aroma. During the boil, S-methyl methionine from malt is converted to the aromatic and volatile dimethyl sulfide. If the boil is not sufficiently vigorous, the boil wort may contain enough residual DMS to be detected in the beer. Many brewers judge the intensity of the boil by how much the surface appears to roll and the term “rolling boil” is applied to wort that is properly boiling. Since wort boiling is so energy intensive there are very real economic reasons to reduce evaporation and the obsession with DMS removal goes hand-in-hand with this pursuit. Excessive evaporation, over about 15%, is also an indicator of excess thermal stress and can lead to problems with beer foam, flavor stability and development of wort flavors undesirable to some beer styles.
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Heh. Obviously, the conclusion to this is PV panels and a battery array. 8) 
Thanks Mark, that’s some good info. I’ll have to cut power back a bit. I usually have it set where I boil away about 1 gal per hour so 4 gal ends up at 3 into the fermenter then 2.5 into the keg after yeast and trub loss.