Cold "mashing"? Is this possible?

I recently did a distillery tour at du nord in Minneapolis, and they said they dont do a hot mash for their grains, but instead soak them at room temp for a while. Their gin and vodka taste pretty good, so they are definitely extracting sugars. I was wondering if anyone does this brewing?
I saw some people cold mash (really not a mash but a steep) their dark grains to prevent roasty bitterness, but i havent seen anything about doing an overnight steep with the full grain bill. I feel like it shouldnt work, but it works for the distillery so i dont know. I know they are using mostly corn, but they are also using rye and their process works with that. The easiest way to find out would be to steep some 2 row overnight and see what the gravity is.
Anybody hear of this? Anyone try it?

Another question might be why do it? But if you could just soak your grains overnight and then sparge and brew the next day, that would be a simple brew day.

I’m not sure but I believe you will get sugar but also a bunch of nastiness. I don’t think distillers care about that since all they are going for is the alcohol everything else is left behind. The flavor from whiskey is from the barrels. Vodka and gin from additives. Correct me if I’m wrong.

You’d get some flavor but starches don’t convert to sugar till a higher temperature. Think it’s around 140 degrees,

I believe there are some amylase enzymes that are active at lower temperatures, but I don’t think they occur naturally in malts. Not a problem if you want to buy the enzyme in bulk and add it to the mash…

Not sure if that is what they do, but Brew cat is right, distillers have different priorities than brewers. Off flavors are not a problem for them, because they can get rid of those during the distilling process. Before it goes in the barrel or gets the additives, it is just tasteless vodka.

I think they add the amalase, now that you mention it. Hmmmm. Just seemed interesting. They started doing it that way bc they didnt have enough funds to get a mashing system for corn (which mashes at higher temps than barley, btw).

Another question i have is this: the first thing that distills out of a mash is methanol, so is any methanol in the mash of a beer or is that just a corn byproduct? Or a result of the distilling process?

They don’t actually cold mashing like you think. Yes grain are at room temp soaking but conversion isn’t happen there. This is where the science come on to play. They create a vacuum this is where conversion takes place. By having the vacuum they lower the boiling point and the energy it take to get to boil. Let’s just say room temp is 5 degree Celsius which is 70 degrees Fahrenheit give or take close on the math. With the vacuum they boil is 70 degrees room temp

Methanol is a byproduct of yeast fermentation, you do get tiny amounts of it in beer. You get more in wine, because it can also form when pectin breaks down. But it is only dangerous when it is concentrated, like you would get from distilling.

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Okay, this was bugging me so I’ve been emailing back and forth with the distillery, and here is some more info.

They do, in fact, cold “mash” their pre-distillate liquor (not sure what it’s called…not wort) by adding amylase to the corn and letting it sit at room temp for an extended period of time. And no, damian_winter, they don’t use a vacuum. In fact, they explained why that wouldn’t work if you were doing it to boil at lower temps. It wouldn’t really be useful for brewing though, because of a few problems.

First, you have to let the mash sit for a long period of time, which makes it more susceptible to unwanted stuff fermenting your wort. They solve this by adding their yeast while they add their grist, along with a decent amount of beet sugar. The amylase is slowing converting the corn’s starches to sugar, and the yeast is converting that to alcohol in the mash. The yeast can convert the beet sugar when their isn’t enough sugar from the corn, and that crowds out unwanted yeast.

So it’s pretty much a mash and fermentation all in one, because as the starch is converted to sugar, the yeast convert it to alcohol. Meaning you wouldn’t be able to do a boil afterward with hops because you’d boil out the alcohol. So while it works for distilling (since you want to boil out the alcohol), it doesn’t work for brewing.

It was an interesting thing to look into, and the owner was quite helpful with all my questions, so if you’re in the Minneapolis area, think about giving du nord a visit. They have a cocktail room, and they make good drinks. (I won a free drink token on the tour because I knew the requirements needed for a whiskey to be a bourbon, so maybe keep that in mind!)

To end, I’ll directly post the emails below. Sorry this is a long post!!!

"I will try to answer your question (pasted below) in “short” form, but if this is not clear, feel free to email me back. Please excuse typos; I had to rattle this off pretty fast (long day). Also, apologies if you are a commercial brewer and all of this is old news, I am assuming you are a home brewer. I added some other du nordies to this response because they may get the same question.

The low hanging fruit/easy question is whether or not amylase can be active at room temperature. The simple answer is yes it can. All forms of amylase are protein strings that have their ideal temperature ranges. The alpha amylase in your saliva breaks down starches at temperatures well below the 145-155F most brewers do their saccharification mashes at; this is in part because the amylase is not meant to do the whole job, so a lower efficiency is acceptable. The strains of amylase (beta and alpha) that brewers are familiar with is most active in the 140F range but that does not mean it is not active at 70-80F–it is just much less efficient. In a brewing set up, efficiency is key: most single infusion mash brewers do not have time on their said and need to convert their sugars in a short time to prevent the introduction of other nasties to their beer. I imagine your saccharification rests are in the 30-90 minute range… In fact, the only way the amylase would not convert a liquid mash is if the proteins had been denatured by too much heat. If you want a real world example, look to a barley farmer. The amylase brewers use is all (or primarily) sourced from barley The barley has these enzymes because it needs to use them to convert starch to sugar to feed the germinating seed. No seed that I am aware of needs to have temps as high as 140f to germinate, but no seed grows so fast that it would need all of its sugar in less than 90 minutes…

Ok, so we know that an amylase can hydrolyze polysaccharides at lower temps by taking a hit to efficiency (works for every seed in nature). But we also know that this set up is not practical for beer production because the process is too slow to produce enough sugar to support yeastie beasties in any numbers sufficient to crowd out the molds and bacteria that would take over. As was explained on the tour, this is the purpose of sugar beet sugar in our process. The sugar infusion eliminates the bad bugs problem by providing all the fuel the yeast need to take over the mash and thus allowing the poor distiller more time.

Let’s assume ad arguendo that a brewer was willing to add sugar and deal with the unholy beer such a brew would produce; it still makes no sense to cold cook for beer because the temperatures needed to simply convert the barley, wheat, or rye are so low. The entire purpose of cold cooking is to overcome the fact that most corn will not gelatinize via heat at temps below 180ish so time is used instead of heat where heat is not available. Without gelatinization, hydrolysis cannot occur. The grains brewers work with will gelatinize at temps around 130-140 which happens to be in the same range as the prime saccharification temps for β-amylase; for this reason, many home brewers have no idea of what gelatinization is. If your gelatinization temps are the same as your saccrification temps it is by definition not possible to “cold cook.” E.g., our rye whisky is made using the exact same process and temps as our L’Etoile vodka, but the vodka mash is a cold cook process and the rye mash is a standard single infusion mash (the difference: the vodka has corn in it).

Just for fun: your friend’s suggestion of a cold boil would be impractical and ineffective. The idea behind cold boiling is to lower the vapor pressure above the liquid to a point equal to or less than the pressure of the liquid thus causing it to boil. The problem here is that cold boiling is just that: boiling. Starches don’t gelatinize because they boil, they gelatinze via water+heat or water +time. You could cold boil your grains for hours and they still would be rock hard.

In fairness, you asked two specific questions:
“do you guys just let the mash sit at room temp with some amalase in order to convert the starches to sugars?”
“do you think it would work for brewing?”
My answer: yes and no respectively, for the reasons outlined above.

Keep drinkin’ good booze,

And that is all! -Daniel


That’s pretty nice they took the time to answer your questions, and it’s pretty interesting. I’ll have to check them out next time I’m down there.

It depends on the distillery. On the tour they said that, by law, a distillery can add certain ingredients to the vodka without listing it on the bottle if it’s under 2% (I think sugar and citric acid were common). But many distilleries don’t add anything to the vodka, and so any flavor you would perceive would be from the ingredients in the mash.

As for whiskies. the barrel adds a lot of flavor, but the mash plays a role as well (consider a rye whiskey compared to one without rye). Gin has botanicals, so that would definitely be getting flavor from things beside the mash ingredients.

Thanks for the update. I don’t know much about distilling so I enjoyed the post. Know I know more.

Very interesting. I also learned something about distilling.

I have an E-book, on a notebook that is not with me, about building a still and the process to make vodka. It was written by a guy not in the U.S. where it is not legal to distill at home. One thing I do remember about his process is that for vodka he used nothing but table sugar and yeast. Cheap bread yeast I think. He was able to make vodka for about $1 a liter. Higher temps than we would use to ferment and recirculating the sugar water boosted up the alcohol content.

They also use different distillation methods for whiskey and vodka. Whiskey comes from a pot still setup, which is less efficient and allows more of the congeners and other byproducts to remain in the final product, which give pot-stilled liquors more character and flavor. Vodka is made in a column still, which allows you separate out pretty much everything and leaves you with damn near pure ethanol, which is pretty tasteless.

I figured that is the point of vodka. Alcohol to add to something else but no flavor. Gray Goose is still better than the cheap stuff though.

And scotch whiskey from distilled beer! Sneezles61

Thanks sneezles61, now I have to go build a still! That way I can get rid of failed brews without having to dump them down the drain LOL

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