So I am one of "those guys" who is looking at posts trying to figure out what works for home brewing and what doesn't based on others' feedback. So, I finally wanted to contribute... And in case you were wondering, I wanted to step up (and am in the process of stepping up) my batches from 10 gallon to 20 - 1BBL.
And more than that, if you're like me, I wanted an alternative to propane and induction seemed like the way to go...here's my experiment...
I finally went for it and bought a couple 25 gallon Northern Brewer kettles and a 15 gallon one, too (that one is mainly for a rigged HERMS system I am going to set up).
Also, I bought two Duxtop 1800 watt induction cookers (http://www.amazon.com/1800-Watt-Portable-Induction-Countertop-8100MC/dp/B0045QEPYM) from amazon.
I wanted to put it to the test so here is what I had:
*For this TEST, my 25 gallon kettle is on a rigged rail system (if I can upload a photo I will, otherwise I'll attach a link) whereby I put the edges of the kettle on two 2x4's and used cardboard as wedges to fit everything to height and induction plates right underneath the kettle...here's what I got:
**My actual system will not be using 2x4's!!! I only did this as a test to see how fast and and what temperatures I can get my 25 gallon kettle of WATER to certain temperatures**
ADDITIONAL INFO: Water was about 65 degrees fahrenheit , outside temperature roughly 70 degrees fahrenheit, in an open garage, little wind. During the course of the experiment, outside temp decreased to 67. Also, the induction plate on the backside of the garage didn't have the best fan/air circulation so I kept it at a heating # of 8/10 (the max) while the other was at 9/10 (max). I did end up increasing the back induction plate to 9/10 roughly halfway through.
65 degrees: 3:55 PM
78 degrees: 4:05
88 degrees: 4:15
95 degrees: 4:25
104 degrees: 4:35
114 degrees: 4:45
paused and checked 20 minutes later
135 degrees: 5:05
145 degrees: 5:15
and so on...
Essentially, I was getting about 1-1.2 degrees a minute increase with my setup.
But there was a few things to keep in mind. I have the sides of my kettle wrapped in Reflectix (double) but the top was only covered by kettle top not reflectix, which to me meant some heat loss as opposed to being covered by insulation (since we know heat rises). Additionally, and possibly more important, I don't have my kettles drilled for ball valve drains, glass sights, or temp probes, so I had to manually open the top (heat loss) and measure for 45+ seconds the temperature. Last, with ideal conditions, the induction plates would be at 10/10 the entire time.
Keeping that in mind, like I wrote, I was getting about 1-1.2 degree increase per minute. When I get probes inserted/cover the top in insulation/etc. I hope to have a steady/increase that rate (although increasing won't be dramatic/too much).
So that's it. Just my own home experiment.
If anyone wants to know, I am planning on upgrading to 3500 W induction plates in the next 8-10 months. I just don't have the ability to run $$$ 220V extension cords to my appliance outlet. Later I will, but not now. Also, I will be using my 15 gallon kettle (on induction plates) with an added copper coil to act as a HERMS system to recirculate wort to my mash. After I sparge, I plan on using induction to heat to boil.
That's my experiment.