fermenting differences between on grain and off grain

[Stircrazy]

Just wondering if anyone has done both on and off grain fermentation and can tell me the differences they noticed (if any) in the end results.

Thanks
Steve

[Lc 1ace]

When I make my all grain mash, it just seems easier to strain my liquid into my fermenter right then. So I never fermented on the grain. Sorry, wish I could help.

[higgins]

I've done both, but not with the same recipe.

For single malts (or most anything with a lot of barley malt) I sparge (as with beer) and ferment the runoff.

Corn mashes are very difficult to sparge without a lot of loss, so for anything with corn I ferment on the grain. After a few weeks to settle I drain off the liquid, and then squeeze the juice out of the remaining grains.

[Deplorable]

Depends on what you want to make, and how much sticky you want to deal with.
For me I'd rather deal with it after the sugars have been converted to alcohol. YMMV
If you have all the stuff for AG brewing beer, and you have no plans to make spirits with corn, off grain is going to be the preferred method.
If you are by chance trying to duplicate a specific spirit, its best to do the homework and find out how they ferment it.

[shadylane]

My 2 cents.
Off the grain for malted barley used for Irish whiskey or Scotch.
On the grain for anything with corn.
I've tried fermenting off the grain with corn, but it's a pain in the ass and wasted to much fermentables.

[EricTheRed]

Just wondering if anyone has done both on and off grain fermentation and can tell me the differences they noticed (if any) in the end results.

Thanks
Steve

I've done both.
On grain is much simpler. And you get (at least i do) get higher yield so that is my preferred method now.

As to taste, can't really aay there is a difference.

Ta

[Dancing4dan]

I have done both on and off grain for corn and barley mash. Have settled on fermenting on grain for both. I use a BIAB and strain after fermentation then strip or steam strip on grain. Always seems easier to strain corn or barley with a BIAB after ferment to me. Steam stripping just makes it all easier. I do strip / spirit run protocol.

For spirit runs using a LM/VM combo still head on a copper packed column allows heads and tails to be compressed and eliminated or blended back in as desired for flavor. Spirit Distilling into 250 ml jars gives opportunity to remove unwanted flavours.

Barrel aging makes a huge difference in improved product quality over any rapid aging I tried or aging in glass with oak.

Controlled fermentation, good cuts on spirit runs and proper aging make the most difference for me. On grain is done for ease and convenience.

[bilgriss]

If we're "just" discussing fermentation as in the thread title, the main differences would be (I think) yield, temperature, and space.

Fermenting on the grain allows enzymes to keep working on the grain and will ultimately produce just a little more alcohol, depending upon exactly how you mash and how well you gelatinize the grains in advance, particularly corn.

the grain left in the fermentation acts a bit as a heatsink. During the greatest exothermic activity, it will not passively release heat as quickly, insulating the mash. Pros and cons...

Fermenting on the grain requires a much bigger fermenter. If you have small fermenters, this will change the nature of your mash protocol and recipe formulation as well.

If you extend the conversation beyond fermentation, there are a ton of preferences that each of us has, and different reasons for feeling that way.

[still_stirrin]

I lauter my mashes, even my bourbon with 50% corn. I have tried a couple of “on the grain” ferments but they have always gone wild with lacto bacteria, and I didn’t really like the finished product (just a bit too sour). The “sour mash” requires longer aging to smooth but does add complexity to the product (if you wait long enough).

I know many here prefer on-the-grain ferments because of the potential boost to the grain flavors. And indeed it does add a lot of variety to the product. I also believe that the flavors are different, ie - more “tailsy” or “husky” because of the additional organic matter in the fermenter.

When moving the distillers beer to the boiler, you have to be careful not to suck up the settled slurry and there is always more floating matter in the boiler which can potentially scorch on the internal electric element (if you have one). Steam driven boilers have the advantage here.

As Shady commented, working with corn in the mash tun is an exercise that many fear. It is difficult to lauter (sparge) because it tends to “gum up” horrendously. (If you think corn is tough, try a high rye mash sometime.) Getting it to drain often requires “creative measures” to get the liquor to flow through.

I have found that “knifing” the grist, that is, cutting into the grainbed with a thin knife will open channels for the sparge water to flow through and that will wash the sugars down. Sparging is a slow process and I get improved extraction rates when it is just a trickle out. Also, holding mash temperatures at saccarification helps conversion as well as drainage when lautering (I don’t “mash out” my “spirit” mashes though).

Probably the easiest cereal grain the lauter is malted barley, so anyone making a “single malt” spirit should try fermenting “off the grain”. It will produce a delicate, yet “signature” flavor, especially when properly matured.

In the end, on or off the grain ferments will taste different because of the effects of the additional organic matter in the fermenter. On-the-grain ferments will produce more flavors, often described as “earthy” when compared to lautered ferments.

New all grain brewers may prefer on-the-grain simply because they haven’t gained experience enough to manage complex mashing techniques. So, creativity with processes and tools can enhance the experience and make this hobby diverse. We all learn as we explore.
ss

[Tōtōchtin]

We all learn as we explore.
ss

Still_Stirrin what is your reason for not going with steam? Besides the extra cost for materials I don't see a downside if the system was built right.
Tōtō

[tombombadil]

I ferment and distill on the grain because it's easier for me.

Originally I built a steam still so I could make rye without scorching it, but now I use steam for corn mashes too.

I don't really do malt only mashes but I would probably follow the same process of I did, because it's easy for me.

[Stircrazy]

If we're "just" discussing fermentation as in the thread title, the main differences would be (I think) yield, temperature, and space.

Fermenting on the grain allows enzymes to keep working on the grain and will ultimately produce just a little more alcohol, depending upon exactly how you mash and how well you gelatinize the grains in advance, particularly corn.

the grain left in the fermentation acts a bit as a heatsink. During the greatest exothermic activity, it will not passively release heat as quickly, insulating the mash. Pros and cons...

Fermenting on the grain requires a much bigger fermenter. If you have small fermenters, this will change the nature of your mash protocol and recipe formulation as well.

If you extend the conversation beyond fermentation, there are a ton of preferences that each of us has, and different reasons for feeling that way.

Ya I am just talking about fermentation as I have an electric element heated 50L milk can boiler, so I need to clear/filter before going into that.

I do have a 200L fermentation bucket so as long as I can end up with 120 to 140L of liquid for stripping I'm happy.

I am not using enzymes as I am talking about malted barley, so I am using them, just the natural ones in the grain. I may try corn at a later date, but for now I'm just talking about single malt type stuff. but I do Imagin that will give the natural emzymes more time also.

[Stags]

I’m relatively new to the hobby but you can take this for what it is worth.

I did one all grain bourbon run, fermented on the grain, and I haven’t felt the need to do another.

Ultimately the taste was very musty, as if some of the grain had malted whilst in the fermenter. For that reason that jar has persisted in life long after 7 generations of UJSM have been delightedly consumed.

So for the ease of making UJSM vs the mess and heartache of AG I don’t see myself venturing out to AG again anytime soon.

[shadylane]

I don’t see myself venturing out to AG again anytime soon.

Don't give up after one failure.
You will never know if it was due to fermenting on the grain or something else.

[Chucker]

I always do on the grain just because it is easier. At the end of fermentation things settle out well enough to rack into the boiler with no additional filtering.
I also don’t try to strain or squeeze the grain bed as this imposes the same concerns that I’d have about lautering and sparging. Instead I return the backset from the stripping run back to the grain bed, stir, and let it settle again. It’ll easily do this overnite. The resulting liquid is now lower in alcohol content than the initial but still has about 1/2 of the remaining alc by mass that was in the soggy bed of grain. (Not quite, in reality, and based upon overall volume). Just now in a more dilute state. This gets stripped again. And the backset goes back to the grain mass again.
The next run will be the low wines already collected from the two strip runs plus whatever fits in the boiler from the fermenter again. This becomes the spirit run.
It works for me. I’ve been mashing up to 85# grains in a 55 gal drum. Boiler is a 15.5 gal keg.

[jonnys_spirit]

I always do on the grain just because it is easier. At the end of fermentation things settle out well enough to rack into the boiler with no additional filtering.
I also don’t try to strain or squeeze the grain bed as this imposes the same concerns that I’d have about lautering and sparging. Instead I return the backset from the stripping run back to the grain bed, stir, and let it settle again. It’ll easily do this overnite. The resulting liquid is now lower in alcohol content than the initial but still has about 1/2 of the remaining alc by mass that was in the soggy bed of grain. (Not quite, in reality, and based upon overall volume). Just now in a more dilute state. This gets stripped again. And the backset goes back to the grain mass again.
The next run will be the low wines already collected from the two strip runs plus whatever fits in the boiler from the fermenter again. This becomes the spirit run.
It works for me. I’ve been mashing up to 85# grains in a 55 gal drum. Boiler is a 15.5 gal keg.

I've done that a few times too. Topping up with backset is a good idea instead of water to capture a bit more flavor Just top it up once you hit the grain bed to get another run out of it... Disposing of wet sloppy spent grain is sort of a PITA or you can put it off one more time by topping up the fermenter with sugar, molasses, panela for a sugar-head-plus after all the AG strips... Sometimes I'll mash in a little more fresh grain and add panela/molasses/sugar for a rumski run.. Eventually the spent grains are removed and put into compost.

Cheers!
-j

[Stags]

I don’t see myself venturing out to AG again anytime soon.

Don't give up after one failure.
You will never know if it was due to fermenting on the grain or something else.

Well played shady. All things in due time