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Old 06-18-2008, 09:12 PM   #1
Jan 2006
Macomb Twp, Mi
Posts: 132
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I am thinking of stepping up my game and moving to partial mashes. However, I am not ready to be able to do a full boil. So my question is can I do a partial mash as a 2.5 gallon boil and then add the top off water?

And partial mashing is the same procedure as all-grain, correct (hitting temps and sparging)?

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Old 06-18-2008, 09:23 PM   #2
May 2007
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They can be either full or partial boil, depending upon how much grain you use and how much sparge water is used. If you want to use grain as a large portion of your fermentables, plan on boiling more than 2.5 gallons. Brewing software comes in handy here, as you can setup equipment profiles and the program will help you craft recipes that don't exceed your mash or boil capacity.

The mashing/sparging process for partial-mash is no different than all-grain, just on a smaller scale.

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Old 06-18-2008, 09:35 PM   #3
The Blow Leprechaun
Jun 2008
Rockville, MD
Posts: 601
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Yeah, you can do a partial boil with a partial mash. It's pretty much like stepping up from steeping specialty grains.

That said, it may benefit your beer more significantly to do full boils than to do partial mashes.

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Old 06-18-2008, 10:41 PM   #4
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Jun 2007
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typically the reason people partial mash is because they can't do a full boil...ergo they cannot collect all their gravity from grain (at least not without 'wasting' a lot of grain by using a HUGE grainbill and a thick mash).

if you can boil 7 gallons, go AG. if you can't, do PM.
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Old 06-19-2008, 12:19 AM   #5
Bob's Avatar
Nov 2007
Christiansted, St Croix, USVI, US Virgin Islands
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I combine PM with late-addition extract. I look to collect 3 gallons of wort from the partial mash, to which the hops are added. Boil down to 2.5 gallons, add extract, and top off to 5.5 gallons in the primary.

Here's an example:

Black Dog Ale (Robust Porter)

3# 2-row Pale Ale malt
0.5# 60L crystal malt
0.75# chocolate malt
0.25# black patent malt

This partial mash provides me with 3 gallons of wort at 1.037. Boiled down to 2.5 gallons, I have a wort of 1.044.

If I were to top that off to 5.5 gallons, the OG would be 1.020. But the late addition of 4# of Briess Organic Light DME brings the 5.5 gallon OG to 1.051.

Be sure to check your IBUs carefully. The above recipe includes the following hops schedule:

1.5 oz Willamette 5%AA - 60
0.5 oz ditto - 20
0.5 oz ditto - flameout

With the gravity provided by the partial mash alone, the IBUs are 39. With the DME included, ProMash says 30 IBU. Since the wort being boiled doesn't have the DME, the first number is correct.

In summary, I boil a partial brew length with fermentables provided by the partial mash. So it all balances out!


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Old 06-19-2008, 01:32 AM   #6
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Aug 2006
Whitehouse Station, NJ
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PM=Partial Boil when you're limited in both MLT volume and Kettle volume.

PM=Full Boil when you're limited in MLT volume, but not kettle volume.

All Grain= when you're not limited by either.
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Old 06-19-2008, 02:32 PM   #7
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Oct 2005
Oak Grove, Oregon, USA
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The easiest and cheapest way to make this move is to get a VLGB (very large grain bag). Mash in your kettle and 'tea bag' the grains to rinse.
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Old 06-20-2008, 05:27 PM   #8
Jan 2006
Macomb Twp, Mi
Posts: 132
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Well I already went out and got the things to put together a 10 gallon MLT, so I wasn't worried about that space. Maybe I think I am just going to go get a turkey fryer so I can do full boils as well, and just do all-grain then.

Thanks for the help guys.

I am sure I am going to have a few question about AG, as I would like to brew this weekend, but I will start a new thread for that.

Thanks again. You guys rock

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