Friday, December 4, 2015

What the heck is Partial Mash?

First of all thank you for all of the questions and comments.  You all keep me on my toes.

Recently there have been a lot of questions about partial mash.   If you read this blog, you know partial mash is my favorite style of brewing.   there are so many advantages to partial mash for the home brewer.

Advantages of PM
  • More fun than extract - you still get to mash grains and sparge and the fun stuff.
    • It feels like brewing. Sometimes when I do an extract batch, it doesn't feel like brewing. I'm just heating up some stuff on the stove and throwing hops into a boil, for me mashing is the difference that feels like real brewing.
  • Better Taste than extract  - Real all grain flavor -
    • I defy anyone to tell the difference between a high percentage grain partial mash and an all grain brew. I think only industry people and BJCP judges might be able to pick out the differences.
  • More recipe options than extract, you can brew anything.
  • Less cost than extract - extract is expensive.
  • More reliable than all grain or BIAB -
    • The extract (DME) is an insurance policy that protects your needed gravity.
  • You don't have to stress over pH levels water chemistry etc…
  • Affordable equipment - electric turkey fryer is about $100.00  All in equipment is about $250.00
  • Decotion and step mashing are available to you.
  • It’s reliability is repeatable you can brew the same beer with the same results more easily.
  • You control the amount and % of grain that you are using.  I have recipes that are 75% grain.   The DME is there as a buffer, an insurance policy if you will.
  • Takes way less time than all grain. It’s about the same as BIAB

But what is partial mash?

There is a lot of confusion over what is partial mash.  Often brewers (especially on the internet)  define partial mashing as extract with grains.   And guys... that isn't partial mash.   

I would define partial mash as a brew where a significant portion of your fermentables come from a grain mash.  What portion?   Well that is up to you.  I have recipes where 75% of my fermentables come from a grain mash, with the rest coming from dry extract.   I always prefer dry, but sometimes you need a variety that isn't readily available as a dry extract, such as Maris Otter, Pilsner, or even Vienna.  

Does Partial Mash take special equipment?

No, not really.  You don't even have to have a brew bag, but it sure makes life easier.  You can use your extract set up for partial mash.   But if you want to make truly excellent beers, you will need to be able to boil full volume batches.  If you can't brew full volume, you will need to increase your hops.  How much?  depends on how much you are boiling. But at this point you need to get a decent brew calculator like,  or

So how do I partial mash?

Well every one does it a little differently.   Basically, you need a way to mash your grains, and a way to boil your wort.  Chris Colby, the editor of beer and wine journal, uses a couple of 2 gallon beverage coolers.   He still does a vorlauf, and a sparge.   This takes him to full volume.   He tends to add his extract late.  With this method, you only need one big pot and one smaller pot for the sparge.

I do things a little differently. I have multiple mash tuns, after 25 years in brewing. But once, I started BIAB small batch, I realized that BIAB and partial mash could be the very best compatible processes.

So I soak my grains in a paint strainer bag in my electric turkey fryer.   After a 60 minute mash I pull the basket and set it on a grate above the turkey fryer to let it drain.   I then add 2 gallons of water in which I have dissolved my DME.   Then I sparge to volume. It is that simple.  

I hit my numbers or barely exceed every time.  I never have issues related to water chemistry.  I can make nearly the exact same beer every time I brew a recipe.   The flavor is as good as all grain (better than when all grain doesn't go very well).   And, most importantly it is a blast.  I still get to do the fun stuff, mashing, full volume boil, chilling, aerating, etc...

Where do I find partial mash recipes?

Here is one for you...

and here is what to avoid when looking for a partial mash

not a partial mash recipe

Partial Mash recipes are readily available on the internet,  but beer and wine journal is a great source.   I have many of them posted on   And, if you'd like, I am happy to convert any recipe for you.   But remember it is much easier to go from all grain to extract than the reverse.   As you search for recipes look for recipes that have a base grain in them.  Look for recipes that require a temperature controlled mash.  If they don't they are probably just an extract with grain recipe.

Give partial mash a try. It is fun... and I think truly a better process for homebrewing great beer.   This technique is fighting to find it's place in the post BIAB era.  Many brewers just jump to BIAB, which is fine.  Heck I brew as much small batch BIAB as any one.  Over 70 batches this year. But I have been brewing a long time.   I know how to adjust my water.  I know (or have a good idea) what is going on in my mash/wort.   So if you want to crank out consistently great beer... give this awesome method a try.

Answering a question... "do any breweries use partial mash? " Yes. Several brewpubs that I am aware of, but they do it because they don't have space for the grains.  But primarily it is a home brew method.

Answering another question... "can I do large volumes of partial mash?"... yes the largest I have done is 1BBL.  But to do 10 gallons of PM on a 5 gallon BIAB set up is easy.  Just adjust your hops to account for the partial boil

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