All-grain top-ups?

I apologize if this is covered elsewhere. In reading threads I haven't seen it: What effects are there for topping up a small AG boil to make 5 gal batch? I've read for PM and extract and done it. But for AG? Here's specifically what I mean:

I just built my 10-gal MLT to go AG, but still only have a boil kettle that can handle 4-5 gal comfy. I am calculating for that size boil with my brew software, so grain amounts, etc should be covered and okay. For a 5-gal batch, I plan to top up what is needed after boil. Any deleterious effects/good/bad/indifferent? I will upgrade brewpot at some point, but not right now.

This is why I am only able to go PM at the moment. My stove can only handle a 3 gallon boil, since I have to top-up I use DME to make up the rest of the fermentables.

I suppose you could make your wort higher gravity by mashing more grains so the top up dilutes it to the OG you want since you won't be as short in your boil as I am, maybe someone else can comment on whether this would work.

Your issues will be the same as for extract/PM (color, hop bitterness etc) with the additional one of efficiency. As your volume will be limited you won't be able to use as much sparge water to extract the maximum amount of sugar from your mash.

The problem with doing a partial boil with an all grain bill is that you aren't able to do a complete mash/sparge.

If you can only boil 4 gallons, you will lose efficiency because you wont be able to use the proper amount of mash/sparge water.

For instance, if you have a 5 gallon recipe and 10lbs of grain...

10 x 1.25qts = 3.125 gallons of mash water

Lets say your first runnings is 2.125 gallons...Ideally you'd want to sparge with about 4 gallons of water to bring it to around 6 gallons total for your boil.

But if you can only boil 4-5 gallons, you will lose some efficiency due to lack of sparge water.

I hope I made sense.

You're just going to lose effeciency which means you'll leave more sugars in the mash because you can't sparge enough to get them all out. If I were you, I'd pull out the normal 6-7 gallons for a 5 gallon back and split it between two pots.
You can also drain 5 gallons, boil that adding your hops. Then collect an additional 1.5 gallons by continuing to sparge and boil that without hop additions in a small pot. Use this to top up at the end. At least it's not 1.00 gravity water.

It's either that or you might want to scale your batches back to 3 gallons for now.

Split pot is what will work I think. Might be 4 gal in one, 2 gal in another, but hey, that'd work so long as i split my hops appropriately. Thanks!!

I don't think I would worry about splitting the hops. For the most even flavor, I would add the hops to the larger pot and just use the small pot to top off the fermenter. Why make it harder than it needs to be?

jdoiv said:

I don't think I would worry about splitting the hops. For the most even flavor, I would add the hops to the larger pot and just use the small pot to top off the fermenter. Why make it harder than it needs to be?

Click to expand...

Better hop utilization, one would think...more molecules to bind with.

I do the split pot deal when necessary too. Someday I'd like to get a 10 gallon kettle...