Distill on grain

[Scorpster]

Nervously ran my first attempt at distilling on the grain, my BOP has a false bottom, and I have both induction and an internal electric element. I had the induction on high and the internal element at about 25% to help out. The grain was just loose above the false bottom and had been fermenting for a week, so I was worried it may have created a thick muck above the false bottom leading to some "thumping" action, but the grain bed was loose enough to allow good heat distribution being that it was an all barley mash. Don't think I would try it with a corn heavy mash though. I was also worried about getting a clog due to puking, so watched it like a hawk. Overall it ran almost normal with a lot more rocking to the pot. Was a week night so didn't have time to clean out the leftovers yet but didn't detect any scorching, and got good yield, certainly saved time not having to strain. So far I see no reason not to do this again. I see some have used a bag for the grain, but if the bag can spread across the width of the pot, that would reduce convective currents a lot, so I'm not going to try it.

[fizzix]

Heard of folks distilling on the grain, and you've answered some questions I had.
Scorpster, you mind flashing some photos? Especially the false bottom.

The other question that crossed my mind is whether distilling boiled grains produces a facet that off-grain doesn't give?

Congratulations on your setup and success. Loves me some success stories.

[Samyguy]

I've done it in my 6 gallon double boiler, worked out well.
Cook it , pitch it , wait a week ,distill it.

[Scorpster]

My false bottom has fine slots cut across the plate in a herringbone pattern. It sits on a lip just above the internal element. As a comparison, this was actually ferment 2 of the 3 I am running to use a full 25kg bag of malt. The first ferment I separated a lot of the husk material out and put it into a secondary, which I ran last night. Both used the same recipe. I did end up with less total volume but didn't do any ABV tests yet. I tried to run it with the same heat input as the first run. Came out to about 1l less volume (6.5l vs 7.5l) and I think I went a bit deeper on the second run, so intuitively it looks like better efficiency. Just mashed my third ferment this am, definitely going to distill on grain again but think my total volume is going to be too much for a 2.5 run, so a spirit run it is.
When I cleaned out the pot the next day there was little grain below the false bottom and no signs of scorching. Trying this with an internal element may cause some "cavitation" and severe thumping and possibly burning on the element so I'm not going above 25% power to that 3000W element.

[Scorpster]

Update: Ran my third ferment, distilling on the grain, but fell asleep for a while so my collection vessel overflowed (it sits in a sink so no prob there). Think I lost about half. Anyways ran the spirit run last night, and it was definitely the best off the spout so far. Now to do the same with a sack of Bairds Heavy Peated, except the sleep part.
One issue that did arise was my boiler thermo is a bit above the false bottom, so embedded in the bed of grain, so after heating for a long time the temp was not rising, so I shut it down figuring my induction device had failed, but came down 2 hours later and the temp had gone way up, so I fired back up, but that put me behind, and more tired.
Safety notes: Was using induction only, and that has a 2hr auto shutoff. Actually fell asleep with my head on the sink so was RIGHT beside the still! Live and learn...

[Scorpster]

Nother Update: Ran my first of three ferments of the Bairds last weekend. Because I can't heat up at full speed the heat up time was close to two hours for a 50L run, but I started in the early afternoon so no risk of falling asleep this time. So I see that I said above that I wouldn't go above 25% power to my internal element, well I ignored my own advice and went to about 33% power. When cleaning up the boiler there was a little bit of scorch on the top "wall" side of the element. I think this only confirms my prediction of "cavitation". Since this was 100% Heavy Peated malt I don't think this little bit of scorch could possibly be noticeable (and possibly desirable), but I will keep these low wines separate and compare to this weekends strip run.
So far: So distilling on the grain seems to work fine with the right setup, I am still very wary of doing it in my setup. The liquid and heat source, 80% metal barrier, sludge, liquid layer configuration is not conducive to heat transfer. Although I haven't tried using a thumper yet, this setup seems to mimic that effect by vapour bubbling up past the false bottom and through the sludge in particular areas, so you are heating the bottom, then the top, then finally into the sludge layer. And that's with a pure barley mash which is not all that sludgy (say compared to a corn heavy mash).
Finally: This was very nice off the spout, if you like the Islay style.

[Kareltje]

Nice report, thank you!
Do I understand correctly, that you ferment in that boiler too?

[Scorpster]

Yes. Mash, ferment and distill. SO easy, bring water to 153 (started at 155 but adjusted), dump in cracked malt, 2tsp gypsum, stir, sit, stir, leave overnight or like I did this time, pulled back boiler insulation and put fan on for 5-6 hours. Pitch my DADY at 90.
Did another run this past weekend and had a few more thoughts. This time I used induction only, takes a bit longer but no scorching. I also think that you wouldn't want to try and single run with this configuration, the heat distribution is quite uneven, my thermo which is in the sludge was close to 10 degrees cooler than normal when the first drips started coming out, so I expect more than average smearing. I think this also means you want to make sure to run deep, and capture what was late to reach temp. Also I hear peat flavours come through quite late as well. I like to use a 0.5m packed column on my spirit runs to get a good amount of passive reflux, good cuts and the higher ABV allows more later product to be added while still remaining at or above cask strength.

[Kareltje]

Another drawback is the fact that you can not ferment simultaneously with your distilling.
At this time I have one ferment starting, one ferment ready for distilling and one resting to clear.

I must admit: in this case I am more interested in speed and production than in taste.
But I like your solid and simple system too.

[Bushman]

Since we are talking about false bottoms if any are thinking about making or buying a false bottom Jay at NorCal Brewing in Redding California makes his own false bottoms and will build to suit False bottoms if your interested. I have seen his work and it’s really top notch.

[Scorpster]

Karelje: Ran a sack of sweetfeed using seperate primary and two smaller secondaries, also had many advantages...faster run times, more flexible schedule. Just about gone though.

[Scorpster]

So I decided to give this method a try with rice. As I said in another thread I got poor yield and a bit of scorching. My brix reading said my conversion was pretty good, so I thought my ferment must have quit, so I added some sugar, adjusted the ph, repitched some yeast, and watched it bubble for a week. Follow my strip run experience on this thread: (edit)