Planning First Partial Mash

My brewing buddies and I are thinking about doing a partial mash with the goal of making better beer and maybe saving a few bucks by replacing extract with grain.

Given that goal we'd like to replace as much extract with grain as possible.

We currently have a 20 qt brew kettle, and when we're doing a batch we're currently boiling a concentrated wort of about 3.75 gal (15 quarts) and then topping off with the remainder of the water. We cook on an LP burner.

We have two long (13" x 21"???) nylon grain bags which we have been using for straining hops and break out of the wort.

What I'm thinking is that we'd fill up the grain bags and maintain temps at the various rests by carefully monitoring the kettle and applying heat as needed.

A few questions arise:

1) How much grain should we be able to reliably mash given this set up?

2) What efficiency should we expect? (This question probably depends on the answers to questions below, I'm sure)

3) When applying heat to a brewkettle is there "carryover" heat after you turn the flame off? Or put another way, should we turn the flame off a few degrees before we reach a target temp? If so, how much leeway should we give?

4) Should we mash using 2 gal of water and sparge with another 1.75 gal of water? Or should we just mash in the whole 3.75 gal and forget about sparging beyond pulling the bags out and letting them drain a bit?

5) We have a fairly decent sized rectangular cooler which should easily hold 3.75 gal, but it does not have a drain. If we mashed in that instead, how big of a deal would it be to try to gently pour out the wort into the kettle? How big of a deal would hot side aeration be at that point? Would mashing in the cooler make more sense than doing it in the kettle?

Any suggestions of how we can best do this with the equipment we have would be greatly appreciated.

We're very excited having just bottled a batch of Mild last night. It tasted GREAT out of the fermenter. It was a bit hoppy, and we know we overhopped it a little bit for the style, but I'm sure it'll calm down. If it doesn't, heck we LIKE hops.

Thanks!

Moon

I am planning my first PM as well, I will answer the question that I can...

1. I think you can get about 3 lbs of grain in each of those bags, 6 lbs total (source: http://www.austinhomebrew.com/product_info.php?products_id=1059)

2. I asked the question and got answers from 35% to 65%. I am planning worse case 45-50%, best case anything higher. After mashing I am going to take a hydrometer reading and adjust the DME I add accordingly.

3.With direct flame then no I don't think so. There will be some heat left on the stand, between flame and the pot but not much. Kill it when you hit the temp.

4.From the wiki for mashing:

* 1.1 - 1.25 quarts water per pound of grain (2.2 - 2.5 l/kg): American and English style Ales, high gravity beers
* 1.3 - 1.5 quarts water per pound of grain (3 - 3.5 l/kg): dark lagers, decoction mashes
* 1.8 - 2.0 quarts water per pound of grain (4 - 5 l/kg): light and delicate lagers

Click to expand...

I was told that you can sparge with about the same, but I think you can sparge with a little less.

5.You could always siphon. I am going to mash in my bottling bucket with blankets around it.

Hope this helps.

Thanks!

Now can I really fit 6 lbs of grain in two bags into my 20 qt kettle (in 3.75 gal of water or less?)???

If that's true though, I should be able to get 1.020 out of 6lbs of American 2-Row at 50% effeciency. Not bad. That replaces 2.5 lbs of DME.

By my calculation, and using prices online I come up with $4 savings. Now the more important thing is we will have made cooler, potentially better beer!

I'm kind of leaning towards a partial mash version of Brew in a Bag (BIAB) where we mash a total volume (grains + water) of 3.75 gal and then simply let the bags drain.

Moon

I think just letting the bags drain might hurt your efficiency, I can't say for sure.

I can't say on the volume of the grain+water, but if I had to guess, I would say that wet grains have at max a density of 1 qt/lb. This may be pushing it on 20 qts.

I'm just trying to envision those two bags being full to the point where they can just be tied shut and how they would fit in the kettle. I think they'd have to be kind of bent and pushed in there a bit.

Also, I'm thinking zip ties to close them up. Am I missing some reason why that wouldn't work?

Moon

I recommend making a mini MLT for PM. Theyre not that expensive and great for mashing.

Go to the DIY projects forum and youll find it there

Yeah, after the replies here and talking at the LHBS I think there's no reason not to simply mash in a small cooler. It sounds like trying to maintain temp in the brewkettle on an LP burner would be tricky at best.

I'm hoping that our next brew will be a real Partial Mash!