The Mash - part one
MASH (part one)
The first step in our brew day is mashing in.
In its simplest form this is where the hot water from the Hot Liquor tank meets the grist (crushed grain) in the Mash Tun. Our Mash Tun dates back to the 1960’s – an adapted Grundy Tank, made in London it was originally used to ship beer to bars. The Mash Tun is essentially a big pot that allows for the grains to steep in the hot liquor. A false bottom (sieve like feature) allows for the separation of the grain from sugary wort created following resting for 60 minutes+. A byproduct of this step is our draff/spent grain that goes to our closest farm as cattle feed.
Each grist can vary based on the beer. For an IPA we use up to 100% malted barley. Whereas something darker with a more complex malt character can feature up to nine different forms of grain – from our base malted barley we often add flaked oats and wheat for head retention and a thicker body through to roasted barley and chocolate malt. These highly kilned grains add a jet black colour as well as rich, roasted and toasted characteristics.
The key aim of mashing is to utilise the enzymes present in the grain to convert its starch into sugar. The more grain there is, the more sugar available to ferment and hence alcohol content. In our set up a 4.0% Pale Ale grist would total around 90kg whereas an Imperial Stout we run it up as far as we dare ~250kg. This process is best utilised by mashing in at an appropriate temperature to ensure the enzymes can work effectively – generally between 64 and 68 Celsius.
Top tips for mash progress:
- Preheat your Mash Tun – running some hot water through your tun will ensure there is no initial heat loss to the detriment of your mash temperature.
- Ensure the strike water temperature is appropriate for your chosen mash temperature (varies on style of beer)
- As you mash in continually check your mash temperature and adjust temperature of incoming water appropriately
- Do a basic Iodine test to check conversion of starch to sugar
- Vorlauf – recirculate wort through the mash tun prior to transferring to the kettle to ensure any particles of grain that managed to get under the false bottom are filtered out.
Part two next time: sparge, transfer and gravity.
*picture is of mashing out spent grain. No manway (hatch) on our tun means jumping in and digging it out. Due to residual moisture and heat it leads to a solid work out and to sweat out any over indulging in quality control the day before