If you want to make all grain beer, first you have to mash some grain! Here we explore some of the grain mashing basics and just generally how to mash grain. It’s a pretty simple and easy process, but it can be intimidating at first. For a lot of novice brewers, stepping up from extract or partial extract brewing to all grain brewing can be a bit scary. After all, there’s a lot more equipment involved, a lot more time, and a lot more that can go wrong.

The good news is that it’s not as hard as it sounds. Also, the things that can go wrong usually won’t completely destroy a beer. Sure, a novice may stuff up completely and extract no sugar at all, but generally, you’ll just get the wrong amount and kind of extraction, so the strength or body of a beer may be wrong. However, you’ll still have a perfectly drinkable beer.

We’re going to focus on single temperature/single step mashing here. Many brewers will use multiple temperatures in their mash to bring out different enzymes and elements in their beer. Multi-step mashing techniques can often be too difficult to achieve at home, so we’re going to ignore it for now!

Baileys Paddle

Basic Principles of Grain Mashing

Basically speaking, mashing grain involves converting grain starches into fermentable sugars (in this case mostly maltose). This is done by steeping malted grain in hot water, allowing Alpha and Beta Amylase to do its thing and make this conversion happen. This steeping happens under a controlled temperature (more on this later) in a mash tun for about an hour (depending on the recipe).

What is malted grain?

Malted grain simply refers to grain that has been harvested before it is allowed to germinate. From here, it is soaked in water so that the germination begins, then dried before the seeds start growing properly. This allows the release of the Alpha and Beta Amylase enzymes; these would usually start converting the grain’s starches so it can grow into a new plant! However, malting a grain stops this so it can be mashed later and convert the starches more quickly.

Proper Mashing Temperature

Alpha and Beta Amylase are most efficient between 55-72 degrees Celsius (131-162 degrees Fahrenheit). While they’ll work outside of these temperatures, this is where they’re best. However, go too hot, and it’s possible to denature the enzymes and they’ll be useless.

Because of this, it’s important to choose a proper mashing temperature prior to mashing in. Ideally, this temperature is achieved just as the grains are thrown into the mash water. This is where calculating strike temperature comes in. Calculated correctly, a brewer can ensure that when the grain and strike water are combined, their desired mash temperature will be achieved immediately. Use our strike water temperature calculator to work out what it needs to be.

Selecting a mashing temperature isn’t difficult, it just depends on what kind of beer you’re making. Keep in mind the following guidelines:

  • Beta Amylase – works best between 55 and 66 Celsius (131-150 degrees Fahrenheit). This is where maltose will be produced best. For the same grain bill mashed for the same amount of time, lower temperatures like this will create a beer with a high original specific gravity (OSG) as it produces more easily fermentable sugars.
  • Alpha Amylase – works best between 68 and 72 degrees Celsius (154-162 degrees Fahrenheit). Maltose will be produced by Alpha Amylase, but so will some other sugars. Higher temperatures such as this will allow for beers with a bit more body and a lower OSG.

As can be seen above, there is a gap between 66 and 68 degrees Celsius (150-154 degree Fahrenheit) where neither enzyme is at its most efficient. This is OK. Both Alpha and Beta Amylase will still function in these temperature ranges, just slightly less efficiently. However, you get some goodness out of both in these ranges, so it’s perfectly acceptable to use them.

Mash Temperatures for Specific Styles

As mentioned, if you don’t get the right temperature for the style you’re trying to make, that’s fine. This will just mean that the original and final specific gravities for the recipe will be different, so calculating the alcohol percentage of the beer will be different. That’s fine. Learn for next time!

While most home brew recipes should give desired mash temperatures, here are some guidelines for people who are making their own recipes or tinkering with known recipes:

  • Light bodied beers – 63-66.5 degrees Celsius (145-152 degrees Fahrenheit) – this will create clean, low bodied beers ideal for lagers or easy drinkers. Keep in mind you can go lower, but it may be a bit much!
  • Medium bodied beers – 66.5-68.5 degrees Celsius (152-155 degrees Fahrenheit) – this will create a medium bodied beer and is a good place to start if unsure. This is great for general pale ales or other middle of the road styles.
  • Full bodied beers – 68.5-70 degrees Celsius (155-158 degrees Fahrenheit) – this will leave fewer simple (fermentable) sugars in a beer and therefore allow for a beer with more body. Great for porters and stouts! You can go higher than 70 degrees Celsius (158 degrees Fahrenheit), but Beta Amylase is starting to be less useful here.

Of course these are general guidelines and different grains will have different enzyme and starch amounts. So saying something like “lagers should be mashed at X degrees” is a bit pointless. While lagers are generally mashed at lower temperatures, a given grain bill may change things up. So it’s best to just use good judgement, figure out what sort of body is desired, and go from there!

Let it Sit, Then Drain

It’s important to keep the grain at a constant temperature for mashing. For this, a good mash tun that holds a constant temperature is needed.

How long to mash and how much water

This really depends on the recipe, but, for obvious reasons, the longer the mashing process is allowed to happen, the more starch will be converted. A good starting point is an hour. A longer mashing time will allow more of the starches to be broken down further, amounting to more fermentable sugars and therefore a drier, more alcoholic beer. Shorter will keep more big sugars in the wort; these won’t ferment out and will make a more full bodied and sweet beer.

Similarly, the amount of water the brewer is mashing with will affect this as well. A thinner mash slows the conversion sugar conversion (as the enzyme concentration is lower), but will eventually lead to more fermentable sugars. A thicker mash will go faster but will leave behind less fermentable sugars and therefore a maltier beer. A good starting point here is 2.6 litres per kilogram of grain.

Once again, any decent recipe should give guidance on this. Practice makes perfect and recipes can be modified from there.

Then drain and sparge

From here, it’s just a matter of draining the mash tun of all the wonderful sugary liquid. However, it’s best not just start draining.

The first few litres to come out of the mash tun may have husks, flour, other solids, or tannins in it. None of this is desirable in a good wort. Drain the wort into a jug and pour it (gently) back into the mash tun. Repeat this until the wort clears up then let it run freely into a brew pot.

Then comes sparging. This is just adding more hot water to the mash tun to help flush out more of the great sugars that have been converted during the mashing process. Some people prefer batch sparging, which involves allowing as much wort as possible to drain out of the mash tun and allowing the grain bed to settle a little bit before pouring in a few litres of sparge water. Others will use a continuous sparge, which involves continuously adding sparge water to the mash tun and attempting to get a constant flow of wort.

Both methods are valid and are highly dependent on what sort of equipment is available. Try both!

The wort should be drained until the liquid coming out of the mash tun is clear or almost clear. This should indicate that all the sugars have been extracted from the grain.

And the mash is done!

This has just covered the basics. A lot of the explanation of the sugar conversion, or adding extra temperature steps, can get very involved. However, this is a good start to doing a basic mash for all grain brewing. Get on it!