Electric stove-top: how far can you go?

Hi there. I’m Andrew. My introductory post didn’t make it, so I’ll just jump in to the discussion with this one.

So one of the hurdles to agb is finding an adequate heat source. Most just recommend going with a gas burner, but in the case that using a burner is impossible or unsafe (indoors-only, enclosed space, etc.), I am wondering how far one can make a stove-top electric element go.

Given a basic setup of 5gal brew and using an adequate 6-7 gal brewpot, is it possible/practical/intelligent to rely on an electric stove to heat? Granted that it will take a while longer to heat, less precise, etc., but is it still worth it?

Thanks!

Provided you can bring it to a boil, only you can say if it is worth the hassle.  But if that’s what you’re stuck with, consider scaling down to 2 or 3 gallon batches, it will make things go faster.

One other route you can go, is to just boil 2 or 3 gallons, then top it off in the fermentor, just like when doing extract.

To what extent will that affect your mash efficiency? Seems like if you go anything less than the full-volume when mashing, you’ll miss out on important sugars/etc.

I’ve never done it myself, so I can’t answer you that. Might be a candidate for a no sparge mash?  :-\

Your efficiency will be less like that, but it seems like a fair trade off.  When I started AG I only had a 7gal. post so I was limited to 4 gal. boils.  My efficiency was in the low 60s, but I made some great beer.

It really depends on your electric stove and how many burners your kettle spans and how big/powerfull the burners are. I currently have a little apartment size gas stove that wouldn’t work at all for 5 galon boils (6.5 or 7 to start with) except that my kettle spans two of them. I have brewed on electric stoves in the past and if youc an get two elements under your kettle or if you have one of the big new boiler elements it would probably work fine. The big problem is when the boil is done and you want to chill it will take a few minutes for the element to cool down. Also if you start to get a boil over there is no option to kill the heat and let it settle you just have to stir like mad.

I did a few full boil 5gal batches on an old electric stove, it took over an hour to get the water to boil initially and had to have it full blast to keep it at a roll but it did work. I’d hate to see how much electricity i actually used.

My stove top has 2300w coils for the large burners. One of the large burners will boil six gallons in a reasonable time.

Electricity is cheaper than propane–for most of us.

I have a bottom of the line, cheap-o electric stove we bought 20 years ago when we first moved into our house.  It will boil 4.5 gallons pretty easily but seems to struggle above that.  I make a lot of 3.25 gallon all-grain batches with no problem.  My buddy has a fancy new gas stove and can boil over 6 gallons and makes 5 gallon batches in his kitchen.

Or use 2 pots and boil 3 gallons in each.

I used to use a low end electric stove and it took forever to boil even 4 gallons for an extract batch. But how I have a ceramic cooktop with an element that I believe is nuclear powered and it will boil 6.5 gallons as fast as my propane burner. So the answer is - depends what kind of stove you have.

Maybe look into building (or buying, if possible) a heatstick to aid your stove.  Here’s something to get you started.

I make all my beer on my electric stove.  Mostly 3gal batches with the occasional 4+.

Efficiency is largely about the bound water in grain (0.125qt/lb) as a percentage of the total water added.  If you want 3gal of concentrated wort from 10lb of grain, you could add 4.25gal of water in a no-sparge method.  We’ll assume 90% conversion (I don’t typically see 100%) of a 36ppg malt mix, so you’d have 10x36x0.9= 324points of sugar in your 4.25gal of water.  Since the grain holds 1.25gal, you’d get 3.0/4.25=70.6% of that sugar in your 3gal.  That’d be 3gal of wort at 229pts in 3gal or 76ppg.  Boil that then dilute in the fermentor to 5gal gal and you’d have a 1.046 OG beer.

Tom,

Keep in mind that the apparent absorbtion (.125gal/lb or 0.5qt/lb) also includes volume contributed by the dissolved extract.  This makes the true starting volume larger, and the efficiency somewhat lower.  Extract contributes 0.63 L/kg (.303 qt/lb) of volume.  So in the example above the 10 lbs of grain is 36/46.214 = 77.9% extract by mass (10% less if you consider 90% conversion), *10 lbs = 7.8 lbs of extract, *.303qt/lb = 2.36 qts volume.  The efficiency then becomes 3/(4.25+2.36/4)=62%, leaving you with 3 gallons of 1.067 wort or 5 gallons of 1.040 wort, per your method above.

A two runoff sparge would be somewhat more efficient, which can be important when dealing with higher gravity beers.

same as above but split the water so that there are two equal runoffs:

strike water: 11 qt
absorbtion: 10*0.5 = 5 qt
runoff 1: 11-5=6 qt
sparge water: 6 qt
runoff 2: 6 qt

e1=vout/vtotal = 6/(11+2.36) = 44.9%
v_left = 11+2.36-6 = 7.36 qt
e2=vout/vtotal = 6/(11+2.36-6+6) = 44.9%
etotal=e1+(1-e1)*e2 = 44.9%+(1-44.9%)*44.9%=69.6%.

total collected: 6 qt + 6 qt = 3 gal
gravity: .696*324/3 = 75.2 points in 3 gal, or 45 points in 5 gal.

As far as how much a difference this is vs. a full volume boil, you could get about 88% efficiency with a two sparge collecting 7 gallons preboil, which would yield 5 gallons of 1.063 wort at the end of the boil for the same 10 lbs of grain.  Or to put it another way, you can get the same 1.045 wort by using 7 lbs instead of 10.  Not a great example, however, since you’d probably want to back off on the efficiency for quality reasons at this point.

If you are limited to the stovetop method, I recommend substituting some quality extract to get the desired gravity points. If you add 20% of your desired gravity in extract to the boil you won’t be so constrained by the mash. Obtaining good quality fresh malt extract is the key to making quality beer. I don’t think you’ll even notice the difference if you keep the overall gravity contribution in the 20%+/- range.

This is excellent and probably much more viable than propane in my current location, thanks.

I’m knee-jerk averse to adding extract in my first runs with all-grain, but then again, I’m new to agb. What is a good way to predict your gravity in terms of adding X, Y, Z base extract? Any suggested rule-of-thumb?
(I’m assuming you recommend extract only if I end up needing to boil less than the final volume)

Adding malt extract to supplement your OG in an effort to achieve a targeted gravity is a perfectly viable method of brewing quality beer. If you lauter 3 gallons of 1.060 wort and want to brew 5 gallons of beer with a final gravity of 1.050. You would simply add some DME @ 45ppg or some LME @ 37ppg to help boost your final gravity to the desired 1.050.

After lautering 3 gallons of 1.060 wort, add 3 gallons of water and the calculated addition of malt extract to boost your gravity to the targeted range and boil the wort.

If you want recipe specifics just give me your known additions and I’ll help you calculate the remaining ingredients.

Nyakavt, thanks for catching the 0.125gal/lb, I knew that and I think I used it properly in my calculations but typed it wrong.  And I did neglect to account for the increase in volume for the soluble sugars.

I do know that for a 1.050 beer I can get about the same efficiency with no-sparge as I can with a single batch sparge.  It may be that I’m getting better conversion with the more dilute mash and thats compensating to some extent.  I’m sure there is more of a deficit as the gravity goes up.