Partial Mash using mash tun instead of bag

[Kosch]

Hi Folks,

I have a 5gal cooler mash tun with a cpvc manifold. I haven't used it yet, just done some leak tests. I have an AHS Oatmeal Stout mini mash kit that I would like to use this for. Since this is only my 2nd partial mash (first used a grain bag), I am a bit confused.

The instructions say to use 2 gallons of water @ 155 (well, starting at 160), mash for 45mins. This is for 4.25lbs of grains. Then, "sparge" with 2.25 quarts of 170deg water. Then you top off the kettle with 1 gallon and move on to boiling and adding DME.

Now my questions:

1) Should I just use the same water amounts with the mash tun, or should I just plug it all into Brewtarget, setting it for a 2 gallon boil (since that seems to be what you end up with)?

2) What if I were to sparge with more water, and essentially not have to top off the kettle? Would I just end up with higher gravity, or would there be other negative affects?

3) For anyone who has made this kit or similar beers, how long do you recommend I primary for? I've pretty much done 4-6 weeks for all my beers so far.

Thanks all, I appreciate any help I can get!

Kosch

 

[Specwar]

First, that seems to be a bit of a thin mash. That's pushing almost 2 quarts water per lb of grain. But without knowing the exact grain bill, they may have had a good reason for it.

As for your questions.

1). When mashing, the normal grist ratio is 1 to 1.25qt of water per pound of grains. But using a thinner mash (as was suggested in your recipe) will leave you with more wort after your first runnings (at a lower gravity of course). You could run the numbers through software if you wanted to....just don't forget to add the DME as well.

2) If you sparge with more water you'll end up with a lower gravity.

3) I only primary until I hit my target FG.

If you want to post the recipe we could probably help with some more accuracy.

 

[Kosch]

Thanks for the reply Specwar. Here is the grain bill for the PM part:

1/2lb Chocolate Malt
2oz Black Patent Malt
1/2lb Crystal 60L
1lb Flaked Oats
2oz Black Roasted Barlet
2lb Maris Otter

On my question 2, I was thinking of what it would do sparging with more water instead of topping off the kettle (it says to top off with 1 gal to bring to 3 gallons). I think this would make it a little higher gravity (sparge water having sugar as opposed to plain top off water?), but I'm not sure if too much sparge water can cause problems in this case?

Thanks!

 

[Specwar]

Assuming that you you're getting 65% efficiency. This would work out to 92.5 GU's...but you forgot the DME. (Don't forget that's part of the grain bill)

As far as sparging more...it's sort of like the Law of Diminishing Returns from Economics class. The more you do it...the less you get out of it. So I wouldn't waste the extra time and just follow the recipe as is. You won't "hurt" anything by sparging more...but you'll have to boil your wort down more to hit the correct gravity.

RDWHAHB :rockin: