What is a Mash Out and How to Do It?

When it comes to performing a mash out some brewers consider it to be an important part of the beer-making process while others don’t believe it has any effect on the final product and skip it entirely. Mashing involves soaking crushed grains in warm water for 60 – 90 minutes, also known as steeping. The purpose of the mash is to allow the enzymes to convert the starches in the grains into sugars that the yeast can ferment; whereas a mash-out stops the conversion process.

When performed correctly mashing allows the brewer to produce a wort with the precise amount of fermentable sugars they desire; which in turn influences many of the characteristics of the beer including alcohol percentage, mouthfeel, head retention, and how thin or thick the beer will be.

One of the concerns some brewers have is that during the lautering stage the temperature in the wort drops and as it does the enzymes continue to remain active converting the starches into sugars, potentially altering the profile of the wort that the brewer desired; in theory, a mash out prevents this from happening and locks the worts desired profile in.

Mash Out

Put in layman’s terms a mash out is performed by raising the temperature of the mash before proceeding with the sparging process. Doing so stops the enzymes from converting the starches into more sugars, which results in the desired wort profile being locked in.

The higher temperatures used during the mash out will also make the wort less thick or syrup-like and allow it to flow more freely during the lautering stage.

Mash Out Temperature

The ideal mash temperature is 170℉ (76 – 77℃).

How To Perform A Mash Out

If you are able to apply direct heat to your mash tun this is the simplest way to perform a mash out, do so by heating it over a medium to low temperature until the mash temp reaches 170℉, and be sure to stir as you are raising the temperature so the heat is evenly distributed and hot spots are avoided.

If you are unable to apply direct heat then simply add hot water directly to the mash, if you go this route keep in mind you will need to sparge with less water in order to reach your pre-boil level. Recirculate or stir the mash at the mash out temperature for 10 minutes.

Also, be sure to not allow the temp to go any higher than 175℉ (79℃) or you run the risk of having your beer develop off flavors as a result of tannins being extracted at higher temperatures.

Do You Need To Mash Out?

Mashing out and its effectiveness is a somewhat debated topic in brewing, some believe it is essential and others believe it is of no use at all. In our opinion choosing to perform one depends on a few factors, such as the type of grains used and their protein content, as well as the size of the grain bill itself and the efficiency of your system. If you are not sure whether you should perform one err on the side of caution and mash out; it can not hurt your brew as long as you stay within the stated mash out temperature we provided. 

a guy perfroming a mash out.
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If you mash and boil in the same system, like in an all-in-one system, on your way to the boiling stage it is a simple process to perform a mash out, simply leave the grains in the kettle as you are raising the temperature to the boil, and hold it at 170℉ for 10 minutes before, sparging, removing the grains and moving onto the boil.

Pros & Cons of Mashing Out

There are a couple of potential pros to doing a mash out and besides the thought that it is not needed only one con.

The con is that if your mash out temp is too high it will cause problems such as tannin extraction that will result in off flavors. An additional con could be the extra 10 minutes it takes to perform.

Whereas the primary benefit of mashing out is that it locks in the wort profile or the amount of desired fermentable sugars your beer recipe is calling for as well as making the sparge process go much easier by reducing the viscosity of the wort especially if you had had a thicker grain to water ratio. The higher heat allows the wort to flow more freely during the lautering stage.

Last Call

In the end, performing a mash out really comes down to the brewer’s preference. We have not noticed much of a difference if any between beers we did a mash out and ones we did not. However, since we do brew on all-in-one systems a lot we tend to perform the mash out on most beers we brew.

Let us know your experience, do you mash out or not, and why?

P.S. Be sure to pick up your gift of Big Robb’s top 5 favorite beer recipes from his brewpub. Details are on the side of the blog or at the bottom if you are on your phone. Cheers!

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