Troubleshooting the Mash | Mashing the Grains

It may look simple but important things are taking place while mashing the grain for a batch of your favorite homebrew. Starches dissolve, enzymes break them down, and the yeast feeds on the sugars. Your job is to maintain the temperature during this process which allows the enzymes to their job. Complications can occur while mashing the grains; use this Troubleshoot the Mash guide if you find your mash going astray.

Troubleshooting the Mash

I can’t get the temperature of my mash to hold steady — it shoots up and then drops down.

The thick, porridge-like mash often develops hot spots, especially as the grains settle to the bottom of the pot or as the pot sits over a burner. Stir the mash gently for a few seconds before checking the temperature to be sure you’re getting an accurate reading. When warming the mash on the stovetop, only warm it for a minute at a time, then take it off the heat, stir, and check the temperature. It’s really easy to overshoot your temperature mark — warming it in intervals helps prevent this from happening.

My mash went over 153°F — is it OK?

Yes! As soon as you notice, stir the mash off the heat to bring it down below 153°F. You might end up with a slightly lower alcohol level and more malty flavors in your finished beer, but your beer will still ferment just fine.

My mash went over 170°F — is it OK?

Temperatures over 170°F effectively stop all enzymatic activity, meaning you can’t get more sugar in your beer. If this happened at the very beginning or end of your mash and you brought the temperature down as quickly as you could, the beer should be fine. (Also, beers often form hot spots as they warm — stir the mash for a few seconds before checking the temperature for the most accurate reading.) If it was definitely above 170°F for more than a few minutes, though, you might not have enough sugars to ferment the beer. Taste the wort — if it tastes sugary to you, then your beer is probably fine. But if it tastes like starchy water, then best to ditch this batch and start again. Better luck next time!

My mash went under 148°F — is it OK?

Yes! Put it on the heat for just a minute, stirring gently and checking the temperature. Take it off the heat as soon as it hits 150°F (it will continue to rise a degree or two after you take it off the heat). If it was below 148°F for a long time, you may end up with a thinner-bodied beer with a slightly higher alcohol level than expected, but your beer will ferment just fine.

My mash went under 140°F — is it OK?

Yes! See above, and then mash for an extra 15 to 30 minutes to make sure you get enough fermentable sugars in your wort.

Get ready to Mash the Grains by visiting The Hoppy Brewer in Gresham to get your: Stainless Steel Brew Kettle.

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