Fermenting on or off?

Production methods from starch to sugars.

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DavidG
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Fermenting on or off?

Post by DavidG »

Pretty new to the sport and I've done both but I'm curious, are there flavor benefits to either method? It's a hell of a lot easier for me to transfer the mash to the still if I ferment off but I'd ferment on if there are true benefits to the final flavor profile.
I bought a quality mash bag to fit my 30 gal fermenting bucket and now just hoist it up above the bucket and let it sit for an hour. SO much easier.
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Re: Fermenting on or off?

Post by BlueSasquatch »

About a 50/50 split mate, you're easily going to find people who say its better on and just as many who say its better off. Mostly it comes down to personal preference, when do YOU want to deal with the grains? Also there are some with brewers background and equipment that can sparge/rinse grain before fermentation, and opt to go that route.

I ferment on the grain, I figure conversion is likely still taking place to some degree, and any flavor transfer should only get stronger the longer it sits, and once there is a level of alcohol to further breakdown. . .you know, those flavor parts.
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Re: Fermenting on or off?

Post by witch »

Having read some of the threads on this site. Think it come's down to personal choice. some will say you get a better flavor ON others off
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Ben
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Re: Fermenting on or off?

Post by Ben »

Opinions are definitely split. Brewers will tell you that you are going to leach tannins leaving it on the grain, people without that background tell you they get more conversion out of leaving it.... Both seem to make great whiskey, neither is wrong.

For me its easier to sparge at the brewery, let the grain drain off overnight and toss the drained grain, no squeezing required, can rack clear liquid to the boiler after the ferment is done, I get good conversion efficiency so I don't worry about what might be left in the grain. If you don't have those tools a mop bucket is cheap and functional.
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Re: Fermenting on or off?

Post by squigglefunk »

i ferment on the grain, I then drain the grains, add some backset/sugar/water and get a great sugar shine run from that.
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Re: Fermenting on or off?

Post by jonnys_spirit »

Most bourbon distillers ferment AND distill on-grain if that means anything.

I ferment on grain and squeeze but I've minimized my squeezing by doing a second ferment where I leave a bunch of liquid and grain behind after squeezing a little, add some more mashed grains + sugar/panela/mole-asses to get a couple ferments out of the initial AG for a "sugarhead +"... I end up mashing more to get enough liquid on that first AG in the series but oh well...

Not had good luck with sparging corn meal grade corn but some have...

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Re: Fermenting on or off?

Post by 8Ball »

I ferment on grain and squeeze with a paint bag an mop bucket. Its just easier to do it that way for me. Sometimes I do a piggy back sugar head. My stilling opportunities are limited, so I mostly spend the time on AG’s exclusively. I do enjoy a good piggy back sugar head though …
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Re: Fermenting on or off?

Post by BrewinBrian44 »

I ferment on grain and believe it’s a simple process. This was odd to me when I first started this hobby since I’m also a big home brewer. There are pro’s and con’s, but for me, I think the pro’s outweigh the con’s.

The benefits I see are really about simplicity and yield. I ended up purchasing a 50 gallon stainless kettle with a heating element inside. The simplicity comes from doing everything in one vessel from heating the water, fermenting and collecting the finished clear wash with a pump. I believe I also get additional yield because the other half of my wash comes from squeezing it out of the grains in a mop wringer, which gives me almost all the available liquid back, I just need to give it a little time to clear. I believe there’s additional sugar still inside the grain that the yeast gets to work on vs lautering, thus increasing alcohol yield. I can also have a very finely ground grain bed without worrying about a stuck sparge, also increasing yield per pound of grain.

In addition to these points, I have a theory that the extra contact time with the grain must add “some” additional flavor to the final product to be distilled.

I think it really comes down to your equipment that should help you decide.
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Re: Fermenting on or off?

Post by Metalking00 »

After trying to squeeze the grain after mashing, then tracking sticky stuff all through the house on my shoes, Ive switched to fermenting on grain. I just find it easier to deal with.
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Re: Fermenting on or off?

Post by NZChris »

I've always fermented on the grain. It's very convenient, plus I often do a sugar wash on the trub, with and without using backset and feints depending on the desired end use for the product.

I've never read anything that convinces me that I should give fermenting off the grain a try so I haven't tried it yet. Many commercial distillers ferment on the grain and distill with it in their boilers and continuous columns.
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Re: Fermenting on or off?

Post by Twisted Brick »

NZChris wrote: Thu Sep 29, 2022 9:18 pm
I've never read anything that convinces me that I should give fermenting off the grain a try so I haven't tried it yet.
+1

Attempting to 'sparge' a corn-based mash is a challenging exercise in itself, but is also an extra step that exposes the wash to a dangerous temp range that benefits from subsequent boiling to ward off infection. Boiling adds a considerable amount of process time, can skew projected gravity but more importantly, destroys the enzymes that would otherwise continue to work over the course of an un-boiled ferment. Not a simple process, fermenting off-grain adds process time sparging and transferring wash between vessels for a perceived labor saving over simply squeezing a completed on-grain ferment. Metalking00 also makes a good point that squeezing a completed on-grain ferment (replete with alcohol) is much easier than trying to sparge a mass of un-fermented sticky grain.
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Re: Fermenting on or off?

Post by NZChris »

When fermenting grapes, I've only ever fermented pressed juice for wine, never for distilling. Given grapes, I can make several different types of product from the same grapes.

Grain isn't that much different, you can make anything from beer to neutral, to vodka, young white dog and aged whiskey, etc., all from the same grain.
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Re: Fermenting on or off?

Post by Demy »

I ferment and distill on the wheat, I perceive more flavor of wheat / hay ... I make beer so I could filter but I prefer it like this ... The equipment must also be considered ..
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Re: Fermenting on or off?

Post by Ben »

Twisted Brick wrote: Thu Sep 29, 2022 10:37 pm
NZChris wrote: Thu Sep 29, 2022 9:18 pm
I've never read anything that convinces me that I should give fermenting off the grain a try so I haven't tried it yet.
+1

Attempting to 'sparge' a corn-based mash is a challenging exercise in itself, but is also an extra step that exposes the wash to a dangerous temp range that benefits from subsequent boiling to ward off infection.

The mash never hits a temp it wouldn't hit otherwise, can you explain further?

Boiling adds a considerable amount of process time, can skew projected gravity but more importantly, destroys the enzymes that would otherwise continue to work over the course of an un-boiled ferment.
I don't understand the neccesity? I sparge direct to fermenter unless I am using specific grains I have noted to bring over clostridium. If you aren't boiling your mash with grain you don't have to boil it without

Not a simple process, fermenting off-grain adds process time sparging and transferring wash between vessels for a perceived labor saving over simply squeezing a completed on-grain ferment. Metalking00 also makes a good point that squeezing a completed on-grain ferment (replete with alcohol) is much easier than trying to sparge a mass of un-fermented sticky grain.

Turn a valve and let gravity do the work? You just sparge directly to your fermentation vessel, add rice hulls and you can literally sparge anything, including 100% rye, oats or corn.
There seem to be some significant misconceptions about how sparging and lautering actually work... Beer gets boiled for a set of reasons that has little or nothing to do with distilling. If you are set up to sparge you just turn a valve and drain direct to your fermenter. You have to do some math to figure out your volumes but its elementary school stuff...
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Re: Fermenting on or off?

Post by squigglefunk »

sounds like quite the setup
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Re: Fermenting on or off?

Post by Twisted Brick »

Ben wrote: Fri Sep 30, 2022 6:15 am
Twisted Brick wrote: Thu Sep 29, 2022 10:37 pm
Attempting to 'sparge' a corn-based mash is a challenging exercise in itself, but is also an extra step that exposes the wash to a dangerous temp range that benefits from subsequent boiling to ward off infection.

The mash never hits a temp it wouldn't hit otherwise, can you explain further?

Do a search on ‘beer wort danger zone’ and see if your sparge process temp apply. You also said you don't bother to squeeze and just let your hanging grains drain overnight. You didn't specify, but are you then pitching yeast the following morning? It's risky, but members who don't chill their converted mashes manage (a bunch of 'em anyway) to avoid infection and spontaneous fermentation by rogue yeasts. Please ignore my question if you let your grains drain post-fermentation. Your prior posts indicate you prefer to ferment off-grain.

Boiling adds a considerable amount of process time, can skew projected gravity but more importantly, destroys the enzymes that would otherwise continue to work over the course of an un-boiled ferment.

I don't understand the neccesity? I sparge direct to fermenter unless I am using specific grains I have noted to bring over clostridium. If you aren't boiling your mash with grain you don't have to boil it without

I was going on your thread on simple AG bourbon where you noted that you boiled your converted wash for 1-2hrs. The benefit of retaining the integrity of enzymes (endogenous and exogenous) throughout the ferment is fairly well understood, but you’re correct – there’s no rule that says you have to. There are a number of members (and commercial guys) who feel the best whiskey is made from grains that are handled carefully to preserve each grain’s individual character, not boiled.

Not a simple process, fermenting off-grain adds process time sparging and transferring wash between vessels for a perceived labor saving over simply squeezing a completed on-grain ferment. Metalking00 also makes a good point that squeezing a completed on-grain ferment (replete with alcohol) is much easier than trying to sparge a mass of un-fermented sticky grain.

Turn a valve and let gravity do the work? You just sparge directly to your fermentation vessel, add rice hulls and you can literally sparge anything, including 100% rye, oats or corn.

You certainly make it sound so simple, Ben. Would it be possible for you to share your process for sparging 100% rye? I’m sure there are more than a few who would be interested in how you do it (more insight than 'rice hulls'). Details like temps, pH, yield, total process time, and especially your secret on how you achieve a good runoff through all the beta glucan snot.
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Re: Fermenting on or off?

Post by Dancing4dan »

When I started using enzymes everything switched to ferment on grain. Initially I mashed, fermented and distilled in the same pot using my steam still. My situation makes it difficult to deal with a pot full of Backset and spent grain after a run.

Have been using BIAB, yellow label yeast and fermenting on grain. Mashing is done at 35*C. When ferment is complete lift the bag, let it drain. Haven’t bothered squeezing. There just isn’t much grain left over so I just hang the bag and wait for it to drain. After draining with gravity the extra effort does not seem worth the effort for the small amount of extra liquid produced squeezing.

The strained wash then sits in a cold room to settle the trub. Rack off the cleared wash and then leave the trub in a 30L fermenter to settle and further clear for some additional liquid wash. Sits for weeks. This extra cleared wash gets added to a spirit run for some extra flavour in final product.

Guys talk about off flavour doing this but I find if the trub sits long enough in the cold the wash improves.

Two 16 gallon fermenters fill a keg boiler for a stripping run.
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Ben
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Re: Fermenting on or off?

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Twisted Brick wrote: Fri Sep 30, 2022 5:08 pm

Do a search on ‘beer wort danger zone’ and see if your sparge process temp apply. You also said you don't bother to squeeze and just let your hanging grains drain overnight. You didn't specify, but are you then pitching yeast the following morning? It's risky, but members who don't chill their converted mashes manage (a bunch of 'em anyway) to avoid infection and spontaneous fermentation by rogue yeasts. Please ignore my question if you let your grains drain post-fermentation. Your prior posts indicate you prefer to ferment off-grain.

I should have been more clear about this. Once I have pulled what I want out of the mash (I fly sparge) I let the remaining liquid drain into a bucket which gets discarded. The main body of my mash runnings gets further chilled via an immersion chiller

If you are sparging straight to your fermenter (assuming no chill either way) your temps should drop faster when sparging, you have less thermal mass and you are getting more air exposure to the hot wort as its draining to the fermenter.



I was going on your thread on simple AG bourbon where you noted that you boiled your converted wash for 1-2hrs. The benefit of retaining the integrity of enzymes (endogenous and exogenous) throughout the ferment is fairly well understood, but you’re correct – there’s no rule that says you have to. There are a number of members (and commercial guys) who feel the best whiskey is made from grains that are handled carefully to preserve each grain’s individual character, not boiled.

In search of a little quicker day I don't boil anything anymore... unless I am using feed barley in it, I found that the feed barley I have access to seems to have a clostridium problem so I give it a 10 minute boil prior to chilling. If I am concerned about full conversion I will throw in a cap full of SebAmyl GL after chilling, but since I switched to WLP099 I don't even bother with that as it is a glucoamalyse producer, and I tend to let my ferments run long. I need to update that thread, stilling season is almost here.

You certainly make it sound so simple, Ben. Would it be possible for you to share your process for sparging 100% rye? I’m sure there are more than a few who would be interested in how you do it (more insight than 'rice hulls'). Details like temps, pH, yield, total process time, and especially your secret on how you achieve a good runoff through all the beta glucan snot.

It is documented here: viewtopic.php?t=85799. The mechanics are the same as I developed in the simplifying all grain bourbon thread, no secrets. Feel free to ask further questions, it boils down to a beta glucan rest at the beginning and a percentage of rice hulls. Rogenbier (german rye beer) is a great research keyword for learning to sparge sticky grains. I modify my water to Dortmund profile and let the pH do whatever it does during the mash, you will note a small amount of dark malt in there which also helps regulate pH. Efficiencies are good, high 80's, distillate yields are very good, I cut out less feint volume from this recipe than I do any other.



As a disclaimer I do have a very large false bottom which probably helps my runoff times. I have developed the techniques I use because I have a very bad back, I can't lift a mash tun full of wet grains these days. I can scoop the drained grain out of my mash tun, and use pumps for liquid transfer, roll everything around on wheels etc. It is what works for me, if I were tougher I would be more inclined to work on the big on grain ferments...


This photo is rye running off near the end of the sparge, into my immersion chilled vessel, being chilled as it enters. Runoff rate is still good, and even if it was a little slow I could just do something else while it's doing its thing. If I really wanted to speed things along I could build a cheap counterflow chiller and drop direct to the fermenter.
1002211702.jpg

And this is the real payoff, zero solids, great conversion (this is iodine test), distilling day is shortened cuz I don't have to deal with the grain then. Just suck it up on brew days. And I can recycle my yeast to eternity, so the comparably expensive wlp099 just lasts and lasts.
1002211124a.jpg
Edit: I don't know why the pics are being weird... I tried
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Re: Fermenting on or off?

Post by Twisted Brick »

Thanks for the rye sparge link, Ben. And thanks for clearing the other items up. Cooling your mash runnings is a brilliant idea and reduces danger zone temps. No boiling should shorten your mash day a bit, and also eliminate any variances in projected gravities due to different boiling time lengths. One thing I've always wondered about is how a boiled wash protein break impacts a ferment destined to be distilled. Any flavor, behavior differences you see? I've also wondered if the dreaded 'hot side aeration' oxidation can impact flavor of a final distillate like it does in beer, but this is probably really minor.
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Re: Fermenting on or off?

Post by Ben »

I actually feel like boiling it makes it a little easier to control what goes into the fermenter, if I mess up a calc or measurement and have too much liquid before my stopping gravity I can just boil it out to hit the volumes I am going for. That helps keep me from overfilling the still and having a mess. I don't worry quite as much about starting gravity as some seem to. I have a history of brewing very high gravity beers and have a moderate understanding of what it takes to keep the yeast motivated. I am also not in a rush on my ferments, I have plenty of fermenter space so if I want to brew something a little stronger I just increase the ferment times, use the correct yeast nutrients and bulk up pitch rates.

As far as hot break goes, I am not sure. I still get it in my still after getting it in the brewery, and have to be careful if I overfill. I don't have a good understanding of the chemistry that takes place when this happens, it would be interesting to know what is created and consumed. I don't fully understand cold break either. I have considered attempting to remove the hot break at the brewing stage, but I haven't messed with it yet so I have nothing side by side. I had hoped that I might be able to pull the hot break out in the brewery boil and fill the fermenters more, but it's easier not to. I also don't know how or what protiens contribute to the distillation process. In beer they are important for head retention, body and mouthfeel but we have none of that once its been through the still. It seems like most of those things in liquor come from oils.

I feel like hot side aeration (HSA) is really overblown, I used to worry about it when I brewed beers for competitions, I would pump to the bottom of vessels, avoid splashing, really go out of my way to prevent it, I never could detect a difference. I usually use a length of hose on the tri-clover out of that port, and dump to directly above the element in that vessel. I took it off for the photo... I don't go out of my way on it any more. If you were really worried you could certainly take steps to avoid it, the counterflow chiller would do a good job of this, just feed straight to the bottom of your fermenter. In fact I think if someone was inclined they could use their distillery condenser to drop quite a bit of temp out of their mash on the way to the ferment vessel. It's just tough if you have solids in the mash.

I would much rather chill fast and reap the benefits of that then worry about HSA. When I got the ability to chill my wort it was the first major step in producing beer that I was really proud of, and it saved a ton of time. I still think wort chilling was the biggest single step up I ever made in my process. Simple immersion chiller works for just about everything.
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Re: Fermenting on or off?

Post by Thedevilswater »

Hello,

This is an interesting read, personally I have been fermenting off the grain due to space because I use a 5 gallon bucket. I expect if I could split the mash into two equal fermenters after mashing it would be interesting.

In the coming months I will try a side by side and do exact same recipes all the way through using my normal technique and only vary on grain fermentation to see if the result is dramatically different.

I have purchased some interesting grains to try in some of my next runs. I may try to do a side-by-side there as maybe a cherry smoked malt or a chocolate malt would come through differently. If it's left longer and part of the ferment it's hard to say some of this is an art, not a science and as long as it tastes good it's all good.

I will do my best. Remember to post my results once I do some experimentation.

I'm sure my wife will roll her eyes when she sees double the amount of barrels for the same amount of output, but that's okay. There's been a lot of eye rolling since I started this hobby.

I think she called herself a whiskey widow.
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