Can I brew an AG batch with a partial boil?

So I'm in the process of building my mash tun, a 52qt picnic cooler.

Currently I'm still brewing on my electric kitchen stove so I can only do 4-gallon partial boils for 5 gallon batches.

Is it possible for me to make moderate (1.055) gravity AG 5-gal batches with a 4-gal partial boil?

Let's say I need to mash 11 lbs of grain @ 1.25qt/lb, that's 3.43gal mash water, maybe loose 1.5 gal to grain absorption? that means I can sparge with about 2 gallons of water to end up with 4 gallons of wort pre-boil....

Is this doable? I'm really not trying to do 2 pot brew days! I'm still trying to locate a deal on a propane burner and a 10 gal brew pot to do full boils.

Thanks.

Yes. Its like doing a partial boil extract. You'd use plain water to get your final volume. You could also just do 3 gallon batches. I find my beers are better this way.

Yes.

I would just buy a bit more grain so your boil gravity is higher.

Here's some math:
Target 5 gallons at 1.055, so 5 x 55 = 275 gravity units
275 gravity units / 4 gallons preboil = 69 gravity points
So you should target a preboil gravity reading of 1.069

After boiling for an hour, say you're down to 3.25 gallons. 275 gravity units / 3.25 gallons = 85 gravity points, so 1.085 post-boil

3.25 gallons at 1.085 + 1.75 gallons water at 1.000 = 5.00 gallons at 1.055

Skelator said:

Yes. Its like doing a partial boil extract. You'd use plain water to get your final volume. You could also just do 3 gallon batches. I find my beers are better this way.

Click to expand...

There has to be a limit though since you need at least 1.2qt/lb mash water and need to sparge with enough water to get decent efficiency, right? My mash runnings + my sparge runnings can be no greater than 4 gal for my current setup to work.

I proffer a simple way for you to calculate your beers using your brewing program and getting the boil volume you want. Do 3 gallon batches, set your batch size to 3 gallon, now if you want a 7% beer, you simply shoot for in your program a beer 40% higher in alcohol content. Then post boil you have 3 gallons 40% higher alcohol content than what you want, you top off with 2 gallons and you end up at roughly where you wanted to be with a five gallon batch.

I want a 7% beer

7 x .4 = A

A = 2.8

Target ABV to shoot for in program for 3 gallon batch size - 9.8 %...this makes up 60% of your final 5 gallon product, the other 40% having no sugars should lower you down to a concentration that would put you at about 7.

Or do 4 gallon batch sizes with your program, and shoot for abv's 20% higher and gravities 20% higher, then add your water constituting the last 20%

dbhokie said:

I proffer a simple way for you to calculate your beers using your brewing program and getting the boil volume you want. Do 3 gallon batches, set your batch size to 3 gallon, now if you want a 7% beer, you simply shoot for in your program a beer 40% higher in alcohol content. Then post boil you have 3 gallons 40% higher alcohol content than what you want, you top off with 2 gallons and you end up at roughly where you wanted to be with a five gallon batch.

I want a 7% beer

7 x .4 = A

A = 2.8

Target ABV to shoot for in program for 3 gallon batch size - 9.8 %...this makes up 60% of your final 5 gallon product, the other 40% having no sugars should lower you down to a concentration that would put you at about 7.

Or do 4 gallon batch sizes with your program, and shoot for abv's 20% higher and gravities 20% higher, then add your water constituting the last 20%

Click to expand...

I use hopville to design my recipes and it does allow you to simply input the batch volume (into fermenter) and a separate boil size volume (4 gal) to correctly calculate hop utilization and batch OG after topping off. I've been using this for partial mash batches and my gravities come out to almost exactly what the calculator predicts once I had a handle on what my mash efficiency was.

I've seen electric coil stoves bring 5.5-6.0 gallons to a rolling boil. Perhaps it depends on the kettle you're using. Boiloff rate for me is usually 0.8 gallons per hour of vigorous boil.

To answer your question, of course you can do partial mash indoors. I brew 3-4 gallon batches of 1.070+ OG beers with this method all the time.

To make 3-4 gallons of beer via partial mash, you'll need approx. 2-3 lbs. grain. The rest of your recipe can be comprised of extra light or light DME, or 4-7% corn sugar.

I highly suggest full volume boils though; its makes a better beer for many, many reasons. I'd rather have 3.5 gallons of a really good beer than 5 gallons of something mediocre. What I do now is brew indoors with dual small kettles straddled over two burners each. I boil 3 gallons or so in each kettle and then combine them later in one primary. The only downside to this is cooling. You have to have an ice-bath for one and a wort chiller for the other.

I'd say that will work quite well then. Forage ahead! I was just thinking if you did that you may be able to hit your more desired sparge and mash ratios with your grains, if you calculated doing out 3 or 4 gallon batches. Either way, have fun with your AG experience!

Just want to mention it as I don't think it has been:
you can split up your boil. You can put a pan on each burner to get up to the 5gal mark. Hop adds are a little confusing, but it works.

TyTanium said:

Yes.

I would just buy a bit more grain so your boil gravity is higher.

Here's some math:
Target 5 gallons at 1.055, so 5 x 55 = 275 gravity units
275 gravity units / 4 gallons preboil = 69 gravity points
So you should target a preboil gravity reading of 1.069

After boiling for an hour, say you're down to 3.25 gallons. 275 gravity units / 3.25 gallons = 85 gravity points, so 1.085 post-boil

3.25 gallons at 1.085 + 1.75 gallons water at 1.000 = 5.00 gallons at 1.055

Click to expand...

that's spot on .... I've topped off many all grain batches and they still taste just wonderful ... your efficiency will not be quite as good topping off though ... no biggie ... just add more grain ... cheers !!

The thought of doing 2-pot boils is enough to make me pull the trigger on the 80 qt. Stainless brew pot I've been eyeing and a huge outdoor propane burner. If I'm going to go through the trouble of AG I want to make no less than 5 gal batches. On occasion I may want to make 10 gal batches for parties/weddings, etc. I'm sure you need a powerful propane burner to do 10 gal full boils.

It really doesn't take as powerful of a burner as I thought it would.

A turkey fryer burner suffices for 10 gal for me. I regularly do 8 gall boils easily and quickly.