This post is an overview of my experiences as an induction brewer using the Avantco 3500 cooktop.

Apologies, again, for the long blogging hiatus. Things have been quite busy on the homebrew club side and GTA Brews has eaten almost all of my free time. The club is doing extremely well, over a thousand people in our Facebook group, and about 100 people (growing quickly since it was recently introduced) that have elected to become paid members.

I’ve still been brewing plenty often but haven’t had much time to write up overviews of my recipes. I also recently finished setting up a brand new brew system from the ground up (20 gal Stout Kettles, HERMS, with eBrewSupply BCS panel), so I’m hoping to start blogging more frequently again so I can feature that system. In the meantime I would like to take a step back and write about some of the other brewing system components I’ve put together or purchased over the two and half years I’ve been brewing in that space. I’ve put a lot of thought into every element of my brew space and ensured that they all fit my needs and also balance cost vs functionality in a way that I am comfortable with.

Since I’m no longer using my induction cooktop for every batch I thought I would put together a post about it while it’s still fresh in my mind. I may still use it in the future for odd tasks, or if I ever want to attempt a decoction with my new system.

Over the 3+ years and 90 batches I’ve been homebrewing, 81 of those batches have been on my Avantco 3500 induction cooktop and Bayou Classic brew kettle. When I started homebrewing, in January 2013, Rebecca and I were still living in a tiny 6th floor rented condo in a busy area of Toronto. I had done one batch (1 gal Brooklyn BrewShop) and realized that I was addicted to this hobby and needed to figure out a way to brew full sized batches.

The usual propane burner wasn’t an option (condo), and the stove top was barely able to boil 3 gallons, let alone 6-7+ gallons pre-boil of a full sized batch. After extensive online research I discovered electric brewing and figured that was the way to go. I was left to choose between three options:

1. Installing an element into a kettle
2. Building a heat stick (there were no kits or pre-built ones at the time)
3. Induction

At the time (early 2013), the DIY approach of building a heat stick didn’t appeal to me, and I wasn’t keen on poking a hole in a brand new stainless kettle. Something about the simplicity of induction spoke to me, plus it also seemed a lot safer. After all, I was living in a condo that we didn’t own, and putting an electric element directly into boiling liquid scared me.

I went with induction. After hours of online searches I came to the conclusion that the more common 1800 W (watt) cooktops weren’t powerful enough. Luckily my condo had an in-unit dryer with an accessible 30 A (amp) plug so 240 V (volt) induction was an option. The Avantco 3500 from WebstaurantStore was the only affordable 240 V cooktop so the decision was made.

Note: I don’t doubt that the 1800 W cooktops would work with enough patience but I wanted to make sure that I wasn’t waiting around for hours while the temperature was ramping. I also wanted to make sure that my boil was vigorous enough to get sufficient boil off volume to drive off volatiles.

Picking a Brew Kettle

These days there are several induction compatible brew kettles on the market, but back in early 2013 when I bought my first brew kettle this wasn’t the case. I spent countless hours reading posts on HBT and /r/homebrewing and at the time it seemed to boil down to, if a magnet sticks then it will work. Since then I’ve heard conflicting accounts about whether or not it’s more complicated than that. My current understanding is that if a magnet sticks it will “work”, but a kettle can still work if a magnet doesn’t stick. I believe there is also varying degrees of “work” based on how strongly the magnet is attracted as well. If this understanding of induction compatibility in stainless kettles is wrong please let me know.

When I was picking my brew kettle I read several accounts of people successfully using Bayou Classic branded kettles for induction brewing, so I decided to go with one of those even though it wasn’t officially induction compatible. The one I settled on was the 40 qt Bayou Classic model 1040, I especially loved that it had stamped graduation markings. Finding a Canadian Bayou Classic dealer in 2013 was tough but I managed to find one. I don’t think they are still in that business though since it seems OBK is now the official Bayou Classic dealer.

These days there are several induction compatible kettles on the market, and manufacturers are better about stating this compatibility. Several people I know are successfully using the TallBoy 10 gallon kettle, which is officially induction compatible. I believe this kettle is part of a line of similar brew kettles that started with the Northern Brewer MegaPot, which was one of the first officially induction compatible brew kettles. A quick search shows that SS Brewtech, Spike, and Anvil kettles are officially induction ready. Though not the Blichmann Boilermaker G1 or G2.

These kettles are a functional improvement over my Bayou Classic since they have very flat tri-clad bottoms which help conduct the heat more evenly and are more stable. My kettle has a tendency to rock back and forth on the cooktop if it isn’t perfectly placed, or if I stir a little too aggressively. Also since the active area of the cooktop is only about 10″ in diameter, my single layer kettle tends to form a circle of cooked on trub that needs scrubbing off.

My recommendation if you are just starting out on your journey as an induction brewer, just buy an officially compatible kettle and save yourself the headache. It might even conduct heat more efficiency from the cooktop due to the increased magnetic strength.

Building the Adapter Cord

Before reading this section, read up on what all the NEMA terms and numbers mean (Eg. NEMA 14-30 and NEMA 6-20).

Since the induction cooktop has a NEMA 6-20 plug (240 V), and my condo didn’t have one of these receptacles, an adapter was necessary to plug the cooktop into the NEMA 14-30 (30 A) dryer receptacle. I’m only a computer engineer so I knew enough to know that I needed help designing this adapter. Electronic and digital circuits are a completely different beast compared to 240 V circuits and electrical code. Lucky for me, my dad is an electrical technician so we worked together to design something that we deemed safe enough to use. I would probably have been more hesitant about picking this option if I hadn’t had access to him to help build this.

*Disclaimer*, this cord probably doesn’t meet electric code and probably wouldn’t pass certification by CSA. Since it isn’t hard wired into the house, it counts as a temporary appliance which means it is legal to DIY and make your own, though you may or may-not be covered by your home/tenant insurance if you screw something up. If you aren’t comfortable with this kind of thing, get help from someone that is. That being said, we did our best to design it such that it was safe.

 

Over the years I’ve gotten countless questions about my adapter cable. I’m going to do my best in this section to go over the components I used and how the cable works. We used a NEMA 14-30/14-50 combo plug that works with both dryer and stove outlets depending on which 4th pin you use. The 4 pin of the combo plug is neutral, so I opted to remove it completely so it could be plugged into both stove (NEMA 14-50) and dryer (NEMA 14-30) outlets. I was able to do this because the NEMA 6-20 plug of the cooktop didn’t have neutral, it has two hot pins and one ground pin instead.

Attached to the combo plug is 25 ft of cable. Since the cord was originally designed for my condo’s 30 A dryer plug I opted for 12 AWG, three conductor wire, with 90°C insulation, which is rated for 30 A according to Wikipedia. Over the years I have plugged it into a 40 A stove plug, but technically I should have used 10 AWG @ 90°C for that.

At the end of the cable I have an aluminium box containing a 20 A breaker (red switch), and the NEMA 6-20 receptacle. This 20 A breaker is important because even though the cable is rated for 30 A, the 6-20 receptacle, the cooktop, and it’s cable is only rated for 20 A. This 20 A breaker provides protection and should trip if the cooktop were to ever draw more than 20 A. Also the aluminium box was tied to ground, for safety.

 

 

Most of the items used were things that my dad had lying around in his workshop so I am unable to provide links on where to buy them. Hopefully the pictures and the specs I have provided will help if you decide to create a similar cable for yourself.

Using the Avantco 3500 Long-term

In my 81 batches on the cooktop, I only ever had one issue, a blown fuse inside the cook top. It was straightforward enough to debug with a multimeter and replace that. I never had an issue again after that since I replaced it with a slow-blow fuse. A slow-blow fuse takes a bit longer to blow than a regular fuse, which means that the over-current needs to be sustained for more than just the split second it takes to blow a regular fuse. I’m not sure why it blew the first time. There must be a reason that the Avantco 3500 is so much cheaper than every other 240 V cooktop on the market, perhaps this fluke burnt fuse is related.

Since I used this system for so long, I thought it might be useful to some people to provide some calibration numbers and methods of use I arrived at after dialling in the system.

For someone that doesn’t have much experience with induction brewing it might be tempting to think that it takes longer to heat water compared to other methods like elements or propane burners. I was never once left wanting for more power, and on the occasions when I used this cooktop around other brewers using propane I was usually able to ramp quicker than most of them. Though some of the more powerful ones with 10″ burners were definitely quicker to ramp. I remember when I first got the burner I did some tests with water and I went up about 10°F every time I measured, after that I never worried about ramp times. I don’t have exact ramp times to quote but my opinion is that ramp times were more than quick enough. Sometimes I would even hit boil before I managed to tidy up from the mash and measure out boil additions. There definitely wasn’t time to clean out the mash tun, that was done after boil began.

Boil off is affected by several factors outside the scope of the cooktop, such as humidity and kettle geometry. In my basement, with my ventilation, and with my kettle I had about 1.0 gal/hr of boil off. Meaning that I would begin my boil with 7.25 gal of hot wort to end up with 6 gal of cooled wort at the end of 60 minutes.

Another quirk that needed to be managed was the auto-shutoff feature, which takes action after 2 hours. When doing long boils this would sometimes happen, but it’s easy enough to just press the power button and turn it on again. One way I would manage it would be to just turn on/off the cooktop as I remembered it was almost 2 hours.

Induction cooktops seem to come with two modes, power mode and temperature mode. I never once used the temperature mode. I opted instead to treat the cooktop like a propane burner and simply adjust the power based on how the boil looked. I settled on just using the max power of 3500 W during the boil, and pretty much all other times the cooktop was on. I would sometimes lower the power if it looked like I was boiling off too much volume. I don’t believe the temperature mode is useful since there is no probe to measure, and the jumps in setting value was fairly large as you cycled through using the arrow buttons.

While induction worked great for 6 gallon batches I would hesitate to recommend it for 12 gallon batches. A kettle full with 7+ gal of wort is quite heavy and already significantly over the weight rating of the cooktop. I don’t doubt that it is powerful enough to pull it off, and I’ve heard of people doing it, but I wouldn’t recommend you do it as a matter of course.

Conclusion

Overall I really enjoyed my time as an induction brewer and would recommend this setup to anyone that wants to brew inside without messing with electric elements, a weak stovetop, or doesn’t want to drill into their kettle.

I’ve watched the homebrew market evolve over the last 3 years and there has never been a better time to be an induction brewer than now with all the induction compatible brew kettles that have hit the market lately.

If you have any questions about induction brewing, if there is anything else you think I should have mentionned let me know. If you use the Avantco 3500 yourself, please feel free to leave a comment and let me know if you agree with my opinions!