Maximum practical stove boil

[william_shakes_beer]

OK, I've been thoroughly spankled in my last thread, so the next reasonable follow on thread is... what is the maximum reasonable boil on a residential electric or gas range using a 7.5 gal aluminum brew pot? I don't beileve its reasonable to expect to do a full 5.5 gallon boil, and i'd probably be cleaning up boil overs anyway. I've resigned myself to partial extract boils until Spring when I can get a turkey fryer boiling on a 10 gallon pot outdoors. Can I do 3 gallons in a reasonable amount of time? 4?

 

[Brewer_Bob]

On my gas stove it takes about 40 minutes to bring three gallons to a boil.

 

[nebben]

I struggled to boil 2.5G of wort on my smoothtop electric range. I would not recommend a smoothtop as a brewing platform. If you make a mess, it can potentially damage the cooktop.

If I had a gas range that could do 5.5G reliably, I would probably consider it.

The idea of brewing outdoors is far more attractive to me anyway, since a mess is easily cleaned up, big burners can be used, and any smoke or steam is carried away in the wind, instead of into a space SWMBO is occupying.

 

[Batinse]

I've done six gallon boils on both an electric coil and gas stovetop. It takes about 30 mins, but it boils. I understand not everyone has had this experience, but I brewed that way for almost two years.

 

[captianoats]

I had a really old electric cooktop (built in the 60's) when I bought my house and would do 4 gallon boils all the time. When I put in our new cooktop, I could only do about 3 gallon boils, the new range just wouldn't keep up.

You'll just have to try it. Put 4 gallons of water in the pot and turn it on. If it boils then you can do it. If not, dump out some water and try again.

 

[arturo7]

I've done a full boil on my gas stove. I had the pot straddled over 2 burners.

 

[wonderbread23]

I routinely boil 7-7.5 gallons on my ceramic top burners. I keep the lid on until boil is achieved and then leave it off. Takes about 30-40 minutes on my setup. Note that this is the exception and not the noRm.

 

[Yooper]

I have an awesome gas stove- I can boil 6.25 gallons in a 32 quart pot with no problems. However, each stove is different. Try it with water. If you can boil three gallons, try four, and so on.

 

[OHIOSTEVE]

I do 6-6.5 gallon boils all the time on an electric stove... leave the lid on until it boils hen pull the lid.. good hard boil , losing about a gallon an hour. I also wrap the pot in aluminum foil first ,

 

[Bensiff]

I've done 5 gallon batches on electric, but can't do them on my gas stove...just a matter of how many BTU's the particular model puts out. As long as you have the ability to get it boiling you can easily do a full wort boil with a 7.5 gallon pot, I did for years...a spray bottle will put down boil overs, as well, scooping out the break that begins to develop before the boil reduces boilover too.

You can roughly figure your stoves capacity pretty easy. Water density is about 8.3 lb/gal. Multiply this by change in temperature you desire, this will give you how many BTU's is required to convert a gallon of water to the desired temp. Say your water starts at out of the tap at 55 degrees, so 212-55=157. So, 8.3x157=1303.1 BTU's to boil one gallon. Then multiply BTU by gallons to get BTU required at 100% efficiency.

However, for brewing you will not need those massive increases, your first step will be to raise tap water to strike temp, then heat more strike water which are both smallish sizes that you will not have problems with. The big push is getting your wort to a boil as your heating efficiency drops the hotter you get due to thermal loss to the atmosphere. But, using the above calculation, getting 7 gallons of 145 degree wort to boiling in one hour would require about 3900 BTU's. Your average big burner on a gas stove runs about 10K BTU's. Which would mean in 23 or so minutes (in a perfectly efficient world) you would have boiling wort. However, efficiency sucks in this form of heating so you are going to be waiting a long time to see that wort boil.

Given many things impact efficiency like pot type metal, bottom construction, lid use, is the pot warped, how big it is in relationship to the heating element, etc. I would do a little experimentation. Get your stoves BTU output (or watts if electric and convert to BTU's) then put a known quantity of water at a known temp on to boil in the pot you plan to brew in. Time the operation and you can use these numbers to determine efficiency. From there you can begin to answer if you stove can handle a five gallon volume. Or if the math is too much a headache try to boil a full pot and see what happens, but if you do that a thousand curses on you for not taking advantage of all the work I put into typing this . Good luck.