Partial Mash Brewing

For many brewers, their adventures start with extract brewing – whether liquid or spray malt – and eventually want to branch out into something a little more challenging which will bring more dimension to their beers. All grain might be out of the question for several reasons (for now at least), with a partial mash being the perfect way to step up their beer game.

What is a Partial Mash?

It’s a type of brewing which utilises malt extract as the base fermentable whilst adding adjunct grains to add colour, flavour, extra character etc. For example, a 20l partial mash IPA recipe might have a base of 2.5kg LME and 500g light caramalt for some colour and sweetness.

It’s the benefits of an extract brewing system – less space, less complicated – with added benefits of all grain brewing – more character and depth of flavour to the beer. Grains can even be added to extract kits to “turbo charge” them!

What’s an Adjunct Grain?

For the purposes of this article, it’s a grain which is not the base malt of the beer. Technically speaking, any malt can be an adjunct malt with this description. For example, a beer made with extra pale LME can use small amounts of Munich malt and Maris Otter as adjunct malts despite, technically speaking, they are both categorised as base malts. It’s just in this beer they are in small amounts to add something extra, like colour and flavour, to the beer.

How do I do a Partial Mash?

It’s very simple. Measure out and place the grains you want to use into a muslin bag/mash bag. When your mash water is at strike temperature, place the bag in the water for half an hour to an hour. Remove the bag and carry on with your regular extract brew day.

Does Anything Change from Extract Brewing?

The brew takes a bit longer as you need to wait up to an hour with the grains steeping. Ideally the amount of mash water would change depending on the amount of adjunct grains being used. Grains to absorb some liquid and the final brew may come out short of wort. However, this won’t be a huge amount and it’s possible to top up the wort with boiled water after the final boil has finished.

If you’d like to give this a go, try out these recipes:

Munich Helles
Batch size: 23L
OG: 1.042
FG: 1.008
ABV: 4.44%
EBC: 7.9
IBU: 21.1

Fermentables
Muntons Extra light LME 3kg
Crisp Munich malt – 0.5kg

Hops
Magnum 15g @60 min
Saaz 10g @60 min

Yeast
Fermentis W-34/70

Heat your mash water to 65°C and once at temperature add in the Crisp Munich malt in a muslin cloth or mash bag and leave to steep for an hour. Remove the grains and drain into the kettle. Add the LME and bring to a boil adding the hops at the specified time. Cool to 12°C and add the rehydrated yeast, Once fermentation is complete, store for 6 weeks then bottle or keg as you normally would.

Stout
Batch Size: 23L
OG: 1.057
FG: 1.008
ABV: 6.39%
EBC: 99.9
IBU: 51.5

Fermentables
Young’s Light Spraymalt 3kg
Carafa III 0.7kg
Roasted Barley 0.3kg
Crystal 0.3kg

Hops
Magnum 45g @60 mins

Yeast
Midtbust

Heat your mash water to 65°C and once at temperature add in the Carafa III, roasted barley and crystal in a muslin cloth or mash bag and leave to steep for an hour. Remove the grains and drain into the kettle. Add the DME and bring to a boil adding the hops at the specified time. Cool to 33°C and add the yeast, Once fermentation is complete, package as you normally would.

IPA
Batch Size: 23L
OG: 1.052
FG: 1.009
ABV: 5.62%
EBC: 16.4
IBU: 33.6

Fermentables
Mangrove Jack’s Amber LME 3.5kg
Wheat 1kg

Hops
Magnum 10g @60 mins
Amarillo 20g @10 mins
Columbus 20g @10 mins
Cascade 20g @10 mins
Amarillo 40g @Flame out
Columbus 40g @Flame out
Cascade 40g @ Flame out
Amarillo 40g @ Dry hop 3 days
Columbus 40g @ Dry hop 3 days
Cascade 40g @ Dry hop 3 days

Heat your mash water to 65°C and once at temperature add in the wheat in a muslin cloth or mash bag and leave to steep for an hour. Remove the grains and drain into the kettle. Add the LME and bring to a boil adding the hops at the specified time. Cool to 20°C and add the yeast, Once fermentation is complete, package as you normally would.

Let us know how you got on with your partial mash!