Mashing Processes

There are a number of mashing techniques which a home brewer can use.

"Doing something wrong during mashing, the produced beer can be only a satisfactory one.

Getting it right, the result will be excellent."

Basically we have 3 Mashing Technics for a home brewing.

1. Single Temperature Infusion Mashing

Infusion mashing, as the name suggests is where the malt is allowed to infuse in hot water. Therefore a single temperature infusion mash is a mash at a single temperature. This is the simplest of the three mashing techniques and as such is ideally suited to home brewing.

Due to its simplicity it is the most used style of mashing in home brewing. Generally the temperature applied in infusion mashing is choosen based on the gelatinization and conversion of starch to simple fermentable sugars.

Besides the simplest form of mashing it also requires only basic equipment such as a mash bag and plastic bucket or simple mash tun.

Usually it is based on the temperature optimum of the two main enzymes responsible for the breakdown of starch to fermentable sugars: alpha and beta amylase. However, because you can only mash at one temperature you often find that you select a temperature which is a compromise between the two.

For example the temperature optimum for beta amylase is around 63°C and alpha amylase is 72°C.

Therefore if you go for a temperature closer to 63°C you will favour beta amylase and create a more fermentable beer with a lighter body.

Mashing closer to 72°C, favouring alpha amylase, will give rise to beer of a lower fermentability and greater body.

In reality most brewers select a compromise temperature of 65 – 67°C as this range sits more or less in the middle of the temperature optima for the two enzymes.

The unique infusion for mashing at 65°C is targeted by many home brewers, with optional mash out.

60°C - 65°C

For a more fermentable wort and a lighter beer (with less body) possible, where the 3 enzymes are active, Beta, Alpha and Limit Dextrinase.

Greater breakdown of the starch and carbohydrate chains in simpler sugars, less dextrins.

Take care not to let the temperature pass 65°C, avoiding denaturing the Beta Amylase enzyme.

65°C - 67°C

For a less fermentable wort and a fuller body beer.

Only Alpha and Limit Dextrinase are active.

Less breakdown of starch and carbohydrate chains, average amount of dextrins.

67°C - 70°C

For a fuller body beer (outside the carbohydrate range).

Only Alpha is active, greater amount of dextrins.

2. Temperature Stepped Mashing or Temperature Stops/Ramps

Temperature stepped mashing is where the mash is held for a defined period of time at a particular temperature before being heated up to a second mashing temperature and held.

The number of temperature steps in the programme is controlled by the brewer based on the type of wort that they want to produce.

The main impact of a temperature stepped mash is that the different temperatures which are selected, favour particular enzymes present in the mash.

For example mashing in at 45ºC favours glucanases and proteolytic enzymes encouraging more cell wall degradation and protein breakdown (63ºC favours Beta-amylase and 72ºC favours Alpha-amylase).

Some brewers look at a temperature controlled mash as a way of handling less well modified malt, but by controlling the time that the mash is held at a specific temperature the brewer can control things such as fermentability creating beers with quite different characteristics.

The homebrewer can replicate a temperature programmed mash but they need to have a mash tun which is capable of being heated and good at maintaining temperature.

Example of temperature stepped mashing profile

By mashing in at different temperatures allows the brewer to play with the different enzymes in malt and therefore create beers with different characteristics.

It brings great flexibility to create very different beer types, it can mash poorer quality malt and the wort viscosity is reduced, what helps to transfer it to another vessel.

In the other hand, it requires a mash tun which is able to heat up and control the temperature of the mash.

3. Decoction mashing

Decoction mashing is a version of a temperature stepped mash but has a quite significant difference.

In contrast to a temperature stepped mash, where the mash tun is heated, decoction mashing is a technique where a portion of the mash is removed from the mashing vessel and heated to boiling point in a separate vessel known as a mash kettle.

The boiled mash is then re-introduced back into the mashing vessel with the result that the temperature of the original mash increases. This process can be replicated by the home-brewer but requires an additional vessel in which to boil the mash.

The benefit of a decoction mash is that you can mash in at a lower temperature, typically 45ºC, and then raise the temperature of the mash. This benefits those enzymes that would be de-activated at a mashing temperature of 65ºC.

For example proteolytic enzymes, which are very heat sensitive, are active when mashed at 45ºC but rapidly inactivated at 65ºC. Therefore if you are using an modified malt, where there has been little protein and beta glucan breakdown the lower mashing in temperature is beneficial.

It is also suggested that decoction mashing, because a portion of the mash is boiled, imparts a distinctive flavour on the resultant beer. Some brewers argue that this flavour is actually not as “fresh” or that the beer is more subject to staling whilst the beer is being stored. As such many commercial brewers have moved away from decoction mashing.

It has the same advantages as for temperature stepped mashing, but requires additional equipment in the shape of a mash kettle, it can be tricky to remove the correct quantity of mash from the mash tun to heat up to boiling point, the safety considerations due to the transfer and heating to boiling point of the mash and it woould have a perceived issue with beer flavour stability.

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