Anyone using induction cook ranges?

I was looking into getting an induction cooker for brewing use, but I'm not sure if it's anywhere near powerful enough. Does anyone use anything like this:

http://theinductionsite.com/buy-induction/buy-sr1851.shtml

I'm mainly doing extract brewing so 2.5-3 gallons with everything in it. I was hoping this would bring everything to a boil quicker than my gas stove. Or I could just go with a propane burner. Any thoughts?

Thanks,
Arch

8,600 BTUs doesn't sound like a lot. Most cheap turkey fryers are around 55k. If you are ever thinking of going to AG, and have a good place to use it, I'd go with propane right now. I bet you'll struggle to get a good boil up with this unit (note the description of "fair" cooking power), which will lead you to going the propane route after a couple of brews anyway! Doesn't seem like a very good solution.

Yeah, I was thinking this one was rather small, but they do list some with higher ratings.

http://theinductionsite.com/buy-induction/buy-mc3500.shtml


I'm really just wondering if there's a way to be 1.) more efficient energy-wise and 2)more efficient time-wise over a propane setup.

I've seen these things bring small pans of water to rolling boils in less than a minute. I was hoping it would work as well on a larger scale without having to raising the costs too much.

-Arch

Did I just read that the 25k-BTU-equivalent one was $800?

a turkey fryer may be 55k BTU, but how much of that heat is lost pouring over the side of the pan and into the air? Probably A LOT. You kinda limited by the heat of the flame and the heat transfer ability of the metal. I don't have any scientfic data to back this up but 8000 BTU's induced into the pan may very well be enough to match a 55k air to metal turkey fryer.

sirsloop said:

a turkey fryer may be 55k BTU, but how much of that heat is lost pouring over the side of the pan and into the air? Probably A LOT. You kinda limited by the heat of the flame and the heat transfer ability of the metal. I don't have any scientfic data to back this up but 8000 BTU's induced into the pan may very well be enough to match a 55k air to metal turkey fryer.

Click to expand...

I do believe there is some truth to the heal loss concern, but I still think the difference would be dramatic. A propane burner kicking 50k+ is going to get you a boil pretty quickly. I would be surprised if that puppy could even keep a solid rolling boil going, let alone the time it would take to make it happen. I'd consider the propane proven technology, and this item interesting but no slam dunk.

I use and induction cooker for brewing. I already had one, so I figured why not.

First off - I love my induction cooker!!!! I use it fairly frequently, mostly for standard cooking. It heats just like gas. Turn it on, it instantly generates heat. Turn it off, no heat. The unit itself stays very cool. The only way to burn yourself is to touch the pot. After removing a hot pot, the surface can be touched without burning yourself within about 10 seconds! It is very nice to use in the summer as it doesn't add much heat to your kitchen. Mine is portable so I could cook in my living room if I wanted too. It frequently gets hauled outside to cook there.

They are very very efficient with very little wasted heat - it all goes into the pot.

One drawback - you must use cooking vessels that are magnetic. No aluminum, and MOST stainless steel pots are non-magnetic. When we first bought our unit, we would go to cooking stores and grab a refridgerator magnet and go test all of the pots. We have some magnetic stainless cookware and a bunch of cast iron cookware.

Also - no pacemakers nearby - apparently they can make them go haywire. I do know they make the wire probe thermometers go wacky. My temps we're jumping all over the place (my dial thermometer was not). Turned off the cooker and it immediately stabilized, turned it back on and it went haywire again.

My units is 1400 Watts. I just made the move to all grain and bought myself a 38 qt stainless pot and put a weldless valve on it. My current brewing strategy uses the one pot (and some buckets). I bought some of the insulating bubble wrap and do my mashing on the induction cooker. So far I've just done a single temp mash, but plan on messing with step mashes (as I can easily add more heat). I then drain and sparge into buckets, remove the grains, give the kettle a quick wash and slap it on the propane burner and add the wort (~6 gal) from the buckets.

It takes about 15 minutes for me to heat 3 gallons of strike water to 170 F. During that time I weigh and crush my grains. I use the propane burner to heat my sparge water, and it is faster, but not by a huge amount.

All in all, I'm quite pleased. I haven't yet tried to boil wort on it. My unit will shut off after about 30 min. on high to cool off for a couple of minutes. Then I can turn it back on again. I've processed many gallons of tomato sauce on it though. I can cook 3 gallons of tomato puree down to 1.5 gallon in about 3 hrs - and that is at half power so I don't burn the sauce. I think I could boil wort on high with no problems. If one lived in an apartment and your other option was to use the kitchen stove, I would highly recommend an induction cooker. The stove could still be used to heat sparge water if doing all grain. That plus you can use it for day to day cooking, which you can't with a turkery fryer unless you eat a lot of turkey, or seafood. We like to throw big dinner parties and having an extra "burner" is very nice.

For doing partial boils it would work great. I'm not sure if it would be a whole lot faster than standard kitchen stove. With the costs of gas these days, it is cheaper to operate though - not that it makes a noticible difference in $$ to a hombrewer though. If the $$ of the energy didn't matter, but you still like the idea of saving energy, I'm sure it would do that.

Now the second unit you listed, I bet that would work like gangbusters. 35,000 BTU and all of it going INTO your pot, not around it. If you are only boiling up to 3 gal. this would I think be a bit of overkill (and it requires 240 V)

I did some calculations about using induction elements for brewing.

I want to use one with a built in temperature control device in it to do mashing for a 5 gallon batch, and I figured that I might as well use the same element to boil while I'm at it.

I started with the following tidbit :

"A 3.5-kilowatt (kW) Luxine induction range was shown to boil 20 pounds of water in virtually the same time as a 5.1-kW electric resistance coil (about 15 minutes)."
http://www.appliancedesign.com/CDA/Archives/a9ed6a3235a38010VgnVCM100000f932a8c0____

(conversions with help from google "convert n x to y", in USA)

20 lb water X 0.45359237 kg/lb = 9.0718474 kg

9.0718474 kg X 1 kg/L = ~9 L water (~2.4 US gal)

Not especially encouraging for fast, full boils.

However, I realized that for a full boil, with all grain, you aren't raising the water from room temperature to boiling, you are raising it from room temperature to mashing and from mashing to boiling, so to be fair, I redid all the calculations.

=== Mashing ===

Assume I have 4 gallons of water for mashing, which I could use to process 8-16 lbs of grain (2qt/lb - 1qt/lb), which seems like a reasonable amount.

Now I need to know the amount of heat needed to raise the water from tap temperature (~20C = ~ 68F) to strike temp for mashing (73C = ~163F).

4 gallons X 3.7854118 L/gallon = ~ 15.14 L

Need to change the temperature 73C - 20C = 53C.

1 calorie raises 1 gram of water 1 degree C, 1 gram = 1 ml
so,
1000 calories raises 1 L of water 1 degree C :

15.14 L X 1000 calories/L-delta_C X 53 delta_C = 802,420 calories

I don't happen to think in calories.

1 calorie = 0.00396566683 BTU.
1 calorie = 1.16222222 × 10^-6 kilowatt hours

So that's 3182 BTU, which seems ... low, more on that later. In order to accomplish that in an hour, one needs 0.93 kilowatt hours, so in order to finish in 15 minutes, one needs to apply 4 times as much energy per unit of time, so that'd be almost 4 kWh! To put that in perspective, a good 3.6 kWh element needs a 220V outlet and 16.4 amperes and they seem to cost about $1000+ online. If you can wait a half hour, the a 2kWh element would be fine (much cheaper).

Interestingly enough, the BTU figure looks incredibly low. To the best of my ability to discern, the reason why it takes a while with a 50k - 150k BTU burner is two-fold. First, propane burners only impart 30-60% of their heat to the vessel being heated. Second, the BTU ratings on burners are wildly innacurate. Induction is lauded for its efficiency, which is usually quoted at 90+%. So, technically, all those figures in the above paragraph describe the amount of energy needed, not the size of the appropriate heating element. The induction element at 90% efficiency for 15 minutes would need to be 3.72 * 1.1 = 4.09kWh (I estimated the 4 kWh in the previous paragraph). The BTU figure doesn't make a lot of sense to me, because it would indicate that only a 4772 BTU burner would be needed and that is clearly not the right size burner. A range top is something like 12,000 BTU, and I KNOW it takes more than 15 minutes to raise 4 gallons of water to 73C on that.

=== Boiling ===

We're going from about 73 C to about 100 C, so that's a 27 C difference.

I'm going to assume I did the math correctly, and I'll just say that should be possible for 6 gallons of wort in 15 minutes on a ~ 3 kWh element.



=== Propane Burner Actual Output Estimation ===

I'll do a calculation that figures out how much heat is actually getting into the liquid if someone posts the following : change in temperature, gallons water or wort heated, reported BTU output of propane burner. I think I read somewhere that a 100,000 BTU burner will boil 6 gallons in 15 minutes, but I am suspicious that it was from mash temp to boil, not from tap temperature. That's something like 10,250 BTUs required, so the efficiency is terrible.



=== Checking the Math ===

Starting with the 20 lbs of water example, lets see if my calculations are correct since the BTUs seems way off from what one might expect...

9 L X 80 delta_C X 1000 cal / L-delta_C X 1.16e^-6 kWh / 1 cal X 4 kW_15min / 1 kWh = 3.341

That seems reasonable.

So the element should be 3.341/.9 if it is 90% efficient, which is 3.712kWh. Dang that's efficient (about 95%!!!)!


*************************************
*Please check my math. I'm far from perfect. *
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=== Crazy Ideas ===

I've noticed that large brew kettles with spigots seem to be expensive, as are quality grain mills, and high output burners. So I had this insane idea that perhaps 3-4 of those 1.3 kWh induction elements, each with it's own wee boil pot (~2 gallons?) with a spigot might save big money. The 1.3 kWh elements were available for $65 (!) on the one site. Anyone know where to get smallish induction friendly brew pots with spigots for cheap?

I figure, even if those cheap elements are 80% efficient, one can take 1.5 gallons of water from 20C to 100C in 30 minutes, which is 2-3 times as fast as trying to boil 5.5 gallons on an ancient natural gas range top burner.

Then my only problem is finding a room I can draw 4 x 11amperes @ 120V without tripping a breaker or starting a fire...

I remember a post on a site about a guy with an in-kettle electric heating element who said that whenever he brews, he takes over the laundry room because almost all laundry rooms have a 220V / 15 A outlet for the dryer. That's one of the biggest problems I see with those high kW induction elements for the urban brewer, is figuring out where to plug it in.

My induction unit has a temp setting at 158 F. I haven't tried using it to hold the mash temp. I simply bought a roll of the "metallic" bubble wrap and put about 5 layers around the pot. It easily holds the temp. for 1 hr with no additional heat needed. I really like heating up the strike water IN my mash vessel. No preheating of the tun and I always hit my mash temp dead on.

I'll be brewing again over Thanksgiving weekend. I'll take the initial temp of my strike water and record the time it takes to get to 168 F (or whatever promash calculates for my Bock recipe).

I bought my stock pot from these guys and am very pleased (38 qt)

http://foodservicenow.com/advanced_search_result.php?keywords=stock+pot&x=11&y=14

I had orignally placed an order with InstaWares because they had low prices. The 7-10 days to leave the warehouse turned into 3 months before I finally cancelled the order. Which reminds me, I need to give them a call and remind them to return my money (I cancelled the order 2 months ago - they charged my card 5 months ago!)

Thanks for the advice on the kettles. Have you tried drilling a hole in them for a spigot?

I actually live in a college town, so I was thinking about checking out the local dump for kegs and then building my own keg based system. Unfortunately, that would exclude induction heating from my system. I'm also a little scared of trying to cut sheet metal, but if I can get a 15 gallon keg for... nearly free, I feel like I could save a lot of money.

I'm still kind of amazed that it should be possible for an urban brewer to easily set up an indoor induction based all grain system that could handle 5 gallon batches. My girlfriend wants to live in a city for a while, so I find that to be encouraging if I live in a city with her! It's also nice to know that induction elements are so darn energy efficient.

I'm about to go in search of some homebrew shops to see about making a hopless pumpkin ale (I have a friend who is alergic, and I promised a hopless ale at some point and the rest of my friends are bummed that we only managed to find one 6 pack of pumpkin ale in town).

I drilled my own pot. I fretted over this for quite some time. My original plan was to drill a 3/8 hole and use a reamer to enlarge it. I really did not want to screw up a $125 pot. I finally broke down and bought a step-drill bit (~$35) from Lowes. It worked great! I also used the bit to drill holes in the side of my kegerator.

I've got a buddy hooked on all grain. He talked his wife into starting the hobby by saying he would make several beers to give as Xmas presents. He was doing extracts, but now uses my equipment to do all grain. He needs to get his last batch started so tonight we are going to mash and sparge at my place and then he'll take the wort home and boil it tomorrow night on his own at his place. Therefore TONIGHT I will do the temp and time recordings for mashing on my induction cooker and post them tomorrow.

pjj2ba said:

Therefore TONIGHT I will do the temp and time recordings for mashing on my induction cooker and post them tomorrow.

Click to expand...

.......make that next Monday. Too much other stuff had to get done. I've got two brews ready to put into kegs and that won't happen until Sunday at the earliest

Where did you find this metal bubble wrap? I'd use some! I hunted around online, but I didn't see anything like that mentioned

The way I currently mash is to add hot water to grains in a pot and then collect all manner of blankets, towels and coats available and "insulate" it. Sometimes this results in lots of washing later, and it doesn't seem to do an ideal job of insulating the mash. *sigh*

Right now I'm trying to decide whether to upgrade to a SWIG system or a 3 tier. hmmm... I'm thinking SWIG because I need mobility and I like the idea of brewing several styles at once.

SWIG :
http://www.strangebrew.ca/swig/

I bought mine at the local Lowes. Reflectix foil bubblewrap. There is a picture of the stuff at this link:

http://www.canadianhomeworkshop.com/diy/know_insulation.shtml

I cut slits in the wrap on each side for the handles of my pot, and a notch for my spigot as I wrapped the pot for the first time.

Tonight I'll be doing so brewing so I will report on the temps and times for the induction cooker.

Last night we finally mashed and sparged my friends brew. We started with 3 gallons of water at 70 F (24 C) and it took 40 minutes to get it up to 168 F (85 C). My unit is rated at 1300 Watts. The temperature easily held at 154 F for 1 hr.

OK oznozz, do your calculations. How long would it take to go from 170 F (mash out) to boiling? (6 gallons after sparging). I suspect it might not be too bad. Archie, I bet with a 2500 Watt unit, you would have no problems brewing beer - might even be quicker that a propane burner. Of course a 2.5K unit is not cheap. I think even my little 1300 Watt unit could do the job. One could have two pots going on a regular stove to heat sparge water while mashing.

If one was doing partial boil extracts, I bet my unit could have 3 gallons up to boiling in under an hour. Obviously not as good as a propane burner, but I think it is better than a standard kitchen stove and a real option for people where a propane burner is not an option. The portability of the unit is nice too. A person could still cook a lovely dinner for their significant other while brewing (or just spread their mess out more).

With a 100% efficient, ideal system, it would have taken a .9kW unit 40 minutes to move 3 gallons of water 61 deg C.

That means your setup is 70% efficient, which seems low considering the apparent 92+% efficiency of that Luxine system. more on that later...

So, I would estimate that it would take your unit (at an actual output of 910W) around 30 minutes to move 6 gallons of water 24 deg C (from 76 C to 100 C).

A 2500W unit at 80% efficiency should take 3 gallons of water from ~68 F to boiling in a little under 25 minutes. I estimate that your 1300W setup would accomplish the same feat in 50 minutes.

In terms of energy :
move 3 gal 61 deg C - 692,350 calories OR 2745 BTU
move 6 gal 24 deg C - 544,800 calories OR 2160 BTU
move 3 gal 78 deg C - 885,400 calories OR 3510 BTU

(food calories are actually kilocalories)



The More-On-That-Later-Section :
Did you have a lid on?
Do you know if your unit is one of the kind that will go maximum power for a while and then cool the inductor coil down?
Was it breezy/cold in the heating area?
Did you use an insulated heating vessel?

Of course, maybe that's just standard efficiency, Luxine has a chart that says a generic 2.6kW unit is only about 80% efficient, and more power seems to translate to more effienct, especially if you use a Luxine. *shrug* It'd be interesting to find out the efficiencies of other units.
http://www.luxine.com/advantage.php


Keep in mind that my calculations are pretty simple and they don't take into account fun things like evaporation (lid), loss of heat to the air (except in the "efficiency" sense), etc.


Sorry the reply took so long, Thanksgiving vacation means no math!

oznozz said:

The More-On-That-Later-Section :
Did you have a lid on?
Do you know if your unit is one of the kind that will go maximum power for a while and then cool the inductor coil down?
Was it breezy/cold in the heating area?
Did you use an insulated heating vessel?

Click to expand...

I've got a homemade lid for the pot consisting of 1" thick styrofoam (with one "metalized"side) that I've encased with aluminum foil. It is a pretty snug fit and I rigged it up to be height adjustable so I can keep it just above the liquid surface. The whole thing is wrapped with 5 layers of foil bubble wrap. I mash in the kitchen under a ceiling fan so it is a litle breezy, but it maintains the mash temperature for one hour with no heat additions so it appears to be well insulated.

I don't know if the max power setting cycles on and off. I do know from making tomato suace that if it has been on (not max setting) for an hour or so it turns itself off. I assume to prevent overheating

If a person was doing extract/specialty grain beers and a 3 gal. boil, I think an induction cooker as small as mine would do just fine. Maybe this winter if my brewing schedule coincides with a particularly cold/nasty day, I'll forgo the propane burner outside and try the whole boil on the induction cooker

I agree. I think your type of unit would work well for extract/specialty grain brewing. It'd probably also work for partial mashes, as long as no more than 2.5 gallons of wort was run off (to leave room for the extract!).

I was figuring that while you were heating the pot, maybe some heat escaped somehow, but I'm going to guess not.

I think I'm going to end up putting together a parti-gyle/SWIG style system and brew a strong, a regular and a small batch (5 gallons each). I think that will work on my stove, although I'll still need to buy some equipment. If I move, I'm definitely keeping induction in mind.

I thought I'd give an update on my testing of induction cookers. I brewed a Czech Pislner yesterday. It was cold outside so I thought it would be nice to be outside as little as possible. After collecting my 6 gal. of wort (mashed and sparged with the induction cooker), I started outside on the propane burner and thought that once I had it up to a boil I'd bring it back inside and put it on the induction cooker. Well, all the induction cooker could do was to just barely keep it boiling. I could not get a rolling boil. I ended up taking it back outside to the propane burner for a good rolling boil. Once it got back to a nice rolling boil I went inside and assembled my new router table:rockin: .

So, a 1400 Watt induction cooker is not powerfull enough to keep 6 gallons at a rolling boil. I know it will do at least 2 gallons worth of tomato puree though.

I was looking on the inductionsite.com and they have calculations to compare to a propane/natural gas burner. At 1.4kW you are equivalent to only about 10,000btu when taking efficiency into account. Not a lot of juice to keep 6gal rolling. You can buy much more powerful models, but the price is much more powerful too! Plus they usually draw 200-240V so you would need to probably do some rewiring in the house. If i had the money, which I unfortunately don't, I drop the money on a really powerful model....lots of nice features with induction cookers. Not for your average poor brewer though.