And now we get to enter chemistry class. We’ve talked about grains we use, so let’s talk about the next step: mash cooking and the fermentation process.
Mash cooking (“mashing”) can be explained simply, or you can get specific and dive into the specific chemistry of cellular breakdown, how water temperature and the amount of water used affects the cooking process, and more. For the sake of brevity, we’ll keep things relatively simple in this article, but know that there is a ton of information out there if you want to dig in further. Here are a few places to start.
Ok, so our end goal is to create alcohol that we can then distill, age, and drink, right? Alcohol is a byproduct of yeast eating sugar, which is basically what is referred to as the fermentation process. Prior to fermentation, the starches in the grains need to be broken down into sugars, which creates a thick product called “mash.”
After we choose our grains, we mill them, which means depending on the spirit, we grind them into varying levels of granularity/powder.
We use a vessel called a “mash tun” to cook our grains. To start, we fill the mash tun with hot water. Then we dump in our milled grains and add some enzymes. These enzymes act as a catalyst to help, along with the addition of the hot water, break down the cellular structure of our grains into sugar. Then we let our mixture of hot water, grains, and enzymes (this is our “mash”) sit for a bit.
After the mash has rested for the initial amount of time in the mash tun, we turn the heat back on and bring the mixture to a boil again. We repeat this process a few times – heat and let our mash sit – hitting various temperatures and resting times. Once we feel the mash is ready to start the fermentation process, we transfer the mixture into an open top fermenter.
Fermentation takes time. Once we transfer our mash to the open top fermenter, we cool the mash down to a specific temperature and then we add one final enzyme which is basically a yeast nutrient – it makes the yeast more hungry. Then we continue to cool the mixture. Because yeast is living, if we don’t cool the mash before adding the yeast, we risk killing the yeast.
When we reach our desired temperature, we add our yeast, give our mixture a quick stir, and let it sit for 3-5 days. During this resting process, the yeast will do its thing by eating the sugars from the mash and create alcohol. Once weve fermented to the desired level we are targeting, we distill.
As mentioned earlier, there is both a science and an art to what temperature you boil your mash to and how long you rest your mash. While there are general standards you can follow, each distiller/distillery will have their own feel to the process, and this is one of the areas where distillers get to play and have their own style.
If you missed our previous posts as we unveil the steps taken to make our soon to be released Trestle American Single Malt Whiskey, check them out:
If the hydrometer reads 0, taste it. Is it sour or sweet? The grain bed will continue to bubble up CO2 as it settles and the wash clears. If it’s sour and reading 0, it’s done fermenting.
Emmet Leahy is the Chief Operating Officer and lead product developer at Clawhammer Supply, a small scale distillation and brewing equipment company. He loves the process of developing new equipment for making beer at home just as much as he does using it to brew his own beer. Hes also passionate about teaching people how to use distillation equipment to produce distilled water, essential oils, and with the proper permits, fuel alcohol and distilled spirits.
And now we get to enter chemistry class. We’ve talked about grains we use, so let’s talk about the next step: mash cooking and the fermentation process.
We use a vessel called a “mash tun” to cook our grains. To start, we fill the mash tun with hot water. Then we dump in our milled grains and add some enzymes. These enzymes act as a catalyst to help, along with the addition of the hot water, break down the cellular structure of our grains into sugar. Then we let our mixture of hot water, grains, and enzymes (this is our “mash”) sit for a bit.
After we choose our grains, we mill them, which means depending on the spirit, we grind them into varying levels of granularity/powder.
When we reach our desired temperature, we add our yeast, give our mixture a quick stir, and let it sit for 3-5 days. During this resting process, the yeast will do its thing by eating the sugars from the mash and create alcohol. Once weve fermented to the desired level we are targeting, we distill.
Mash cooking (“mashing”) can be explained simply, or you can get specific and dive into the specific chemistry of cellular breakdown, how water temperature and the amount of water used affects the cooking process, and more. For the sake of brevity, we’ll keep things relatively simple in this article, but know that there is a ton of information out there if you want to dig in further. Here are a few places to start.
Has Fermentation Stopped? How Long Should I Ferment For?
FAQ
How do you tell if your mash is done fermenting?
How can you tell if fermentation is complete?
How long should corn mash ferment?
How do you know if corn mash is fermented?
When 3 weeks have passed, open the lid to the container. You should smell alcohol and the mash should have a foamy appearance. This is letting you know the corn and barley have fermented. Next, strain the mash. You should run everything through a large strainer or cheesecloth to remove any larger chunks of the mash or sediment.
How long does corn mash take to ferment?
Fermentation is the time when yeast works its magic and turns corn mash into alcohol. It’s important the mash is left to rest for approximately 2 weeks. At the end of the 2-week waiting period, wait 1 more week to ensure everything is breaking down as it should. When 3 weeks have passed, open the lid to the container.
How do I know if my fermentation is complete?
For best results, use a hydrometer and check specific gravity at the start of fermentation and when fermentation is complete to ensure that all sugars have been used. This will tell you how much ABV ( alcohol by volume ) your fermentation produced.
How do you make corn mash?
1. Make the Mash The process begins by heating 5-gallons of water to 165°F. When the temperature reaches this point, turn off the heat and add the full amount of corn to the water. It’s important to stir the corn consistently for 5 minutes.