Mashing: turning grain into sugar
Mashing is soaking crushed malted grain in hot water so its enzymes turn starch into sugars the yeast can eat.
What happens in the mash
Malting wakes up enzymes in the barley. When crushed malt is mixed with water at 63 to 69 C, the enzymes (mainly alpha and beta amylase) break starch down into fermentable sugars and dextrins. The sweet liquid that results is called wort.
Temperature decides the beer
A cooler mash, around 63 to 65 C, makes more fermentable sugar and a drier, lighter-bodied beer. A warmer mash, around 67 to 69 C, leaves more dextrins and gives a fuller, sweeter beer. Most recipes aim for 65 to 67 C.
How to do it
Mix the crushed grain with about 2.5 to 3 litres of water per kilogram, stirring so there are no dry pockets. Check the temperature, cover the pot and hold it for 60 minutes. A well-insulated pot or a cool box keeps the temperature steady.
- Heat the water a few degrees above the target to allow for the grain cooling it.
- Stir well, then take the temperature in several places.
- Do not stir again unless the temperature drifts.
- After 60 minutes, move on to lautering.
Equipment
Mash in any clean, food-grade vessel that holds its temperature: a stainless pot wrapped in a blanket, or an insulated cool box. Sanitising matters later, once the wort has been boiled and cooled.