Beer mash is a mixture of water and malted grain (typically barley) which is heated to roughly 150 degrees Fahrenheit (65.5 degrees Celsius). The purpose of making a beer mash is to convert grain starch into sugars that can be fermented by yeast. 

Enzymes found within the malted barley are activated between 140 and 160 F. They shorten  grain starch chains by cutting them into smaller pieces, creating maltose. Maltose is the primary sugar created during the beer mash process. This is a very important ingredient in the beer making process because maltose is easily consumed by yeast during fermentation, which creates alcohol.

Without mashing grains during the brewing process, there would be no sugar for yeast to eat and turn into alcohol, so beer would not exist!

Another common question that people ask is what is the difference between wort and mash? A mash is a mixture of malted grain and water. Wort is the term for the sugary liquid created by the mashing process. In other words, brewers make a beer mash in order to produce wort. Also, a mash contains grain. Wort is typically a sugary liquid that contains no grain.

Beer mash Ingredients

As mentioned above, the primary ingredients used to make a beer mash are,

• 11 lbs. 8 oz. malted barley (pale malt), and
• 7 gallons water.

However these are only the minimum ingredients required to make a beer mash. Many beer recipes also contain other grains in the beer mash such as wheat, rye, oats, corn, and rice. Read our article on beer ingredients for more information.

As detailed in step 7, beer mashing is often conducted for about 60 minutes. However, according to an experiment we conducted, the question of how long to mash beer is one that is up for debate. It may be possible to mash beer in as few as 30 minutes or less.

Beer Mash Equipment

The mash process will go well if you begin with the right equipment, which begins with a proper mash tun. And there are a lot of different types of equipment out there.

Traditional Brewing Systems

A mash tun is simply a kettle or container big enough to hold all of the water and grain necessary for making a beer mash. Many old school homebrew mash tuns made from igloo water coolers. Insulated Igloo or Coleman coolers are cheap and provide a stable temperature enough temperature to allow for semi-precise control of the enzymes that are most active during the beer mash.

Electric Brewing Systems

However new, more high tech mash systems have gained popularity. These systems include electric brew in a bag (BIAB) homebrew systems such as Clawhammer Supply's Clawhammer’s 10 gallon brewing system. They're more pricey, but have a lot of advantages over traditional mash tuns, including the following:

1. You can simply set the temp on the controller versus having to wrap a kettle in a blanket and using a cooler

2. You can also simply turn a switch to activate the pump, as opposed to having to manually collect and pour liquid back into the mash tun.

3. Less equipment. The BIAB system uses a large mesh basket and a single pot vs 3 pots that a traditional brewing system requires.

4. When it comes to “mash out,” you can just increase the temperature on the controller instead of boiling another kettle of water and dumping it into the cooler hoping to hit the target.

BIAB systems typically utilize a method of mashing called “single-infusion mashing.” However, some recipes might call for more advanced mashing techniques, which is something you can read more about in a separate article we have written.

Of course, you’ll need the proper amount of grains and water to conduct the mashing process. You may also need to adjust the chemistry of your water before you begin. You can read more about the impact of water chemistry in our article on that topic.

Advanced Beer Mash Details

If you’re using a non temp controlled brewing kettle, the key to a successful “mash-in” is to ensure that mash water reaches the proper temperature after it's mixed with milled grain. This is a bit more difficult than it seems because when room temperature grain is added to hot water, the grain will actually reduce the temperature of the water. To hit a very specific mash temperature, water will need to be slightly overheated so it drops to the correct temperature after grain is added. This is called the “strike temperature.” To determine strike temperature, use brewing software such as Brewfather, or just use an online strike water temperature calculator. You might need to check your mash every 15 minutes or so to adjust your temperature.

If you’re using a smart brewing system then strike temperature doesn’t really matter. In fact, when we brew beer, we routinely ignore the strike temperature because the controller is able to quickly adjust if needed. Our process is simple, we dial in the desired mash temp on our brewing controller, then add the grain. That’s it. The controller takes care of the rest.

Mash Circulation

Many BIAB brewing systems, including Clawhammer’s, utilizes a pump and hoses to circulate liquid through the grain bed during the mash. Clawhammer’s system actually utilizes a spray valve to ensure that liquid isn’t blasted straight down into the grains, creating a cavity in the middle.

Detailed Mash Temperature guide

Light bodied beers are typically mashed between 145º and 149º degrees Fahrenheit (63-65 C) , while more full-bodied, sweeter styles are mashed at higher temperatures of about 154 to 158 degrees Fahrenheit (68-70C). To split the difference, mash anywhere between 150 and 153 (66-67C) degrees Fahrenheit.

If using an insulated vessel without temp control, you will want to check the temperature at different depths inside the mash tun to ensure mash consistency. If using temp control and a pump, the circulation of liquid will keep temperature even.

Note, exceeding 170F will kill enzymes that convert starch to sugar during the mash. If the mash gets too hot, you can cool it by adding ice cubes or cold water. Conversely, you can also increase the temperature by adding boiling water.

How To Test Your Mash For Completion

Once grains have been mashed for 60 to 90 minutes, you can begin to test that the conversion has reached completion. The most basic test you can perform is taste some of the liquid that’s pooled in the grain bed. If it has become sweet, the mash was a success..

This isn’t typically and also isn’t recommended, but you can also perform a more advanced test using iodine, which can alert you to remaining starch waiting to be converted. Start by picking up a small bottle of “tincture of iodine” at your homebrew shop or local pharmacy. Also get a clean white bowl. Then take a sample of the liquid mash, add it to the bowl along with a drop or two of iodine, and watch what happens.

If the iodine turns a color ranging from dark purple to black, give your mash another 15 minutes before repeating the test.  If the iodine remains rust colored, yellow, or light brown, conversion has finished. If the mash process takes more than a couple of hours, you have likely erred in your temperature calculations somewhere along the line or mashed in too hot and denatured the enzymes in the malt.

To Sparge or Not to Sparge

Brew in a bag brewing typically does not involve sparging. It can, but it typically doesn’t. Efficiency will be reduced slightly, but most brewing software accounts for this.

If you are using the brew-in-a-bag method and are hell bent on some sort of a sparge, you can also take out your grain bag and place it in a separate container. Then add water heated to 167 degree F (75 C) and let the grains steep for between 1 to 10 minutes. Then lift out the bag and then pour the liquid back in with the rest of your sweet wort. But note, adding  water to the recipe that was not accounted for during recipe creation could actually reduce ABV, not increase it.

If using a traditional mash tun without a basket, you will “sparge” or rinse the grains to collect as much of the converted sugars from them as possible.  The simplest way to tackle this is by pouring two to three batches of water that is heated to the same temperature as your grain bed into the mash tun, stirring it, and then letting it rest before running it out of your spigot. You could also vorlauf or recirculate your wort by draining your wort through your spigot and then pouring back over the mash several times until the wort flows clearly out of the tun.

Once you've completed all the steps to separate your sweet wort from your grains, you’re ready to move on to boiling wort – which is the final step before kicking off your beer’s fermentation cycle.