Mashing and Sparging Methods

Mashing is a tool that all grain brewers use to convert the starches in grain into fermentable sugars. If you're new to all-grain brewing or are ready to take the leap from extract, this is a great article to get your feet wet. If you're contemplating between extract vs all grain brewing, one difference is that you will need to mash in order to brew all grain beer.

What is Mashing? What is Sparging?

Mashing and sparging are two separate steps that most (I'll get into this) all grain brewers use to turn the grain into fermentable sugar. Mashing is soaking grain in water at a certain temperature (or several temperatures) over a period of time to create sugar for yeast to ferment. Sparging (this is the step not all brewers do) is a process that some all grain brewers use to rinse as many remaining sugars as possible out of their mash.

I say some, because with BIAB (Brew In A Bag) brewing, a sparge is optional, but can help boost efficiency. However brewers using more traditional brewing methods (three vessel systems), sparging is regarded as a requirement.

Mashing Methods

The Mash involves soaking grain in hot water to convert starches to sugar The Mash involves soaking grain in hot water to convert starches to sugar

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First I'll go into different mashing methods employed by all-grain brewers.

Single Infusion Mash: This is the simplest of any all grain mash, and it's "step" is still employed even if you're doing a more complicated method. Essentially you're holding the crushed grain in water at a certain ratio at a certain temperature for an hour. Yes. You can mash for shorter or longer periods of time, but for simplicity's sake, an hour.

The temperature of the mash dictates a few things about your beer. First, a higher temperature mash will convert faster than a lower temperature mash. A lower temperature mash may take a bit longer to convert all of the sugars. So why not mash at a high temperature all the time to be done faster? Well, grains mashed at a higher temperature will be less fermentable than those converted during a lower temperature mash. The average range for a "normal" mash is about 150-153F. This range is sort of the Goldilocks of mashing. Not too hot, not too cold, just right. So in a single infusion mash, your goal is to hold the mash in that temperature range for an hour, and you're good to go.

You can also test if your mash actually succeeded in converting the starches to sugars using an iodine test (lead image). To do this, remove some of the liquid (no grain) and place it in a shallow pool. A plate or small vial works well for this (you only need a little bit). Next drip a few drops of iodine tincture (available at your local drug store), into the sample. If it turns black, conversion is not complete. Give the mash another 15-20 minutes and try again. If it doesn't turn black, you're good to go!

If you're wondering how much water to use, a ratio of about 1 quart of water per pound of grain will suffice. BIAB brewers typically have a thinner mash, as they include what would be their sparge water in the initial mash.

The all-grain for dummies explanation: Soak crushed grain at 1 quart per pound of grain at 150F for an hour. This is a great way to look at it if you're feeling intimidated.

Step Mash: This is very similar to a single infusion mash, except you are stopping at certain points to achieve different things. For example you may mash at 120F for 15 minutes, raise it to another temperature, and do another rest.

  • Acid Rest (95-113F - 15 minutes): Breaks down glucans that could create a gummy mash. An acid rest also lowers the mash Ph.
  • Protein Rest (113-128F or 131-137F - 30 minutes): Breaks down longer chain starches to reduce haze. Unless you are working with under-modified malt, you should use the higher temperature range. The lower range may decrease head retention.
  • Saccharification Rest (147-154F - 60 minutes): This is your single infusion mash. The temperature range varies outside of the listed range, but going higher will create more unfermentable sugars and lower temperatures will create dryer beer and conversion may take longer.

Cereal Mash: Cereal mashing involves removing a portion of your barley (around 10%), an adjunct like flour, corn meal etc, and creating a thing porridge out of it. It is then brought to a protein rest (122F) for 30 minutes. Next you raise the temp to a regular conversion rest (150F) for about 30 minutes. Lastly you boil the mash for 30 minutes. This gelatinzes the starches and allows them to be converted. The cereal mash is then added to your regular single infusion mash.

Decoction Mash: On a very basic level, a decotion mash is when you do a step mash, but instead of raising the mash temperature via direct heat, you remove a portion of the mash, and boil it. It is then added back in to the mash to raise the temperature to the next step in the mash. This was originally done because maltsters were not as efficient, so many malts were under-modified. Brewers also didn't have a way to measure the temperature of their mash accurately. Homebrewers today do them to get more unique flavors out of their beer despite using only one or two malt varieties.

Sparging Methods

Sparging refers to rinsing the remaining sugars from the grain and getting them into your beer. There are two ways to go about it, with an extra hybrid method for Brew in a Bag (BIAB) brewers.

Batch Sparge: Once your mash is completed, you drain the entire wort into your boil kettle. Then you add more hot water back into the mash tun (with the grain), stir, and let it sit for around 20 minutes. Then drain it again. This would be repeated until you have your boil volume or the Ph of the wort is no longer ideal.

Fly sparging Fly sparging

Fly Sparge: This method constantly adds hot water to the mash at the same time that it drains slowly into the boil kettle. Ideally the water level should be just above the grain bed. To help spread water evenly, a sparge arm is used, which spins and distributes water across the grain bed.

Dunk Sparge*: This is the hybrid method I mentioned. It's something I adopted being a BIAB brewer. After you remove the bag of grain, dunk it in another vessel of water. Usually a couple gallons will work. Remember to account for your total boil volume when using BIAB with this method. The reasoning behind this is to dilute more sugar into the dunk sparge water. Your wet grain will always be holding onto sugar. Sugar in the grain will dilute into the sparge water and the grain will hold onto less sugar in the end. This method is good for 2-4% higher efficiency, and is especially helpful if you don't have a hoist system for your BIAB setup.

Having a grasp of what mashing and sparging involve is a great first step into brewing all grain beer. In fact, after the mash  and sparge, it's no different than extract brewing really. You never need to move beyond a single infusion mash and batch sparge to make incredible all grain beer. Cereal and decoction mashes add more tools to your arsenal, but they aren't required, and in many cases there are alternatives (flaked oats and rye are already gelatanized so they can be used in a cereal mash). If you're looking to brew your first all grain beer, check out our all grain kits and revisit the E-Book!

by David Doucette
David is a full blown fermentation enthusiast who has dedicated much of his free time to learning and sharing the art of homebrewing. He's spent several years documenting and writing homebrewing information on his blog Hive Mind Mead. He's written over 60 articles between Homebrew Talk and Homebrew Supply.
written by David Doucette

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