AG mash (Jimbos) and stripping runs

Many like to post about a first successful ferment (or first all grain mash), or first still built/bought or first good run of the still. Tell us about all of these great times here.
Pics are VERY welcome, we drool over pretty copper 8)

Moderator: Site Moderator

Post Reply
NZDamon
Novice
Posts: 16
Joined: Fri Jul 28, 2017 5:06 pm

AG mash (Jimbos) and stripping runs

Post by NZDamon »

Became impatient waiting for Aliexpress/Ebay purchases of a hot plate and voltage regulator, and decided to go ahead and do my first stripping runs using my brewing gas burner.

In testing out a el-cheapo hot plate, I had done a water run on my new 5L copper alembic, and subsequently a sacrificial alcohol run (to see if the hot plate performed any better with alcohol present - it did not). But I realised I had neglected the vinegar run - so back I went to run through 1 cup vinegar in about 2-3L water, and then re-ran the sacrifical alcohol I had collected the last time around, followed by a decent water rinse.

Scaling Jimbos recipe down to my batch size, I had mashed 5.5kg of distilling malt with 22L of water at 71C to achieve a 65 mash. I added 2g gypsum to the mash, and left it for 3 hours, stirring once every half hour or so. This I cooled to around 24C and poured grain-and-all into a sanitised fermentor, gave the mash a quick blast of oxygen and pitched 1 packet of rehydrated US-05. Original gravity was 1.055, and this went down to 1.000 after a couple of weeks (apparent ABV 7.37%). At this stage I strained/squeezed about 20L of the mash into another vessel, which I left to settle out.

I'll be honest, it did not smell pretty. Presumably wild organisms on the malt had produced a bunch of butyric acid (vomit smell), and it smelt halfway between that and overripe/rotten feijoas. I'd read other people have had similar problems and still got a good product, so I gave it a couple more weeks. The butyric hadn't gone completely but it was much reduced and the fruity/feijoa smell increased.

I charged the pot with just under 4L of the mash (about 75% capacity) and started heating. Fitted the head, sealed and checked for leaks, started cooling... and puke. Too much, too fast. I was expecting this to be fair, so I slowed heating down a bunch, and run real slow (steady drips nearing but not quite a pencil stream). Discarded 50ml of foreshots, and collected about 700ml of 32% in one jar. After that I kept collecting down to 10%, and kept that in a separate smaller jar.

After cleaning the still from the puking, started the second run with less volume, gentler heat (any lower and the gas putters out), and a couple of small squares of butter, which worked a treat. Again I collected down to 10% in about 40 minutes, all up collecting about 1L of 28%.

On run #3 I tried using a couple to Tbsp of olive oil to knock down foaming - didn't really work and I got another puke (may have also over-heated early on). After that, I went back to the butter (much better results). Again I collected about 1L of 30%, and continued collecting down to 10% in a separate vessel.

So after 5 runs, and about 5-6 hours total running time (across two weekends), I now have about 5L of ~28% low wines to do spirit run(s) with, in addition to some deeep tails which I understand age nicely in a whisky. Hoping the hot plate/voltage reg turn up soon, as I really need a gentler heat/more precise control at the low-end to do the spirit run - although this time I won't have the mash puking to contend with.
IMG_20170930_161329.jpg
IMG_20170930_161343.jpg
User avatar
bilgriss
Site Donor
Site Donor
Posts: 1687
Joined: Fri Feb 05, 2016 2:28 pm
Location: Southeast-ish.

Re: AG mash (Jimbos) and stripping runs

Post by bilgriss »

You will find the spirit run not to be prone to puking. You've removed all the proteins and things that contribute to foaming, and it won't be an issue.

Do some reading regarding running small stills, and make sure you have run through Kiwi's guide to cuts several times before you get started. Since you have a tiny still, use very small collection jars.
Cristi
Novice
Posts: 15
Joined: Fri Aug 25, 2017 12:00 am

Re: AG mash (Jimbos) and stripping runs

Post by Cristi »

I was reading your thread and I understand that you added the yeast without actually doing an yeast started.
What I do is take 1L of the wash and add 1L of water, the temp should be around 26-28C , then pitch the yeast and leave it to work for a couple of hours. After you see cool activity in your small starter you can just add it to your wash and things should start to kick and fermentation should take a couple of days instead of weeks and you could stay away from bad smell.
Also make sure that your yeast has sufficient nutrients, because if you yeast is struggling to burn the sugar it will actually develop some rotten egg smell or taste that are difficult to remove. So add sufficient nutrients.
I also use Safspirit M1 but it's just a matter of availability and you can always use what is available in your area.
This is what i add to my fermentation
Safspirit M-1 
1.12 g / L
Actimax Ferm (Actimax Ferm is an activator of alcoholic fermentation containing phosphate,ammonium sulfate, inactive yeasts and thiamine)
0.3 g / L
Calcium Carbonate
0.5 g / L

The Calcium Carbonate and the yeast activator I add them to the wash, not to the Yeast starter.
NZDamon
Novice
Posts: 16
Joined: Fri Jul 28, 2017 5:06 pm

Re: AG mash (Jimbos) and stripping runs

Post by NZDamon »

Cristi wrote:I understand that you added the yeast without actually doing an yeast started
That's correct. I homebrew, and the calculator I use indicates a single 11g packet of dry yeast is a sufficient pitching rate for a clean beer with a starting gravity of 1.061. Additionally 30 sec of pure oxygen run through the wort should have made for a fairly clean fermentation. I would have been more worried about over-pitching yeast doing a starter from dry yeast, which could result in under-attenuation and a higher level of acetaldehyde.

Yeast nutrient certainly wouldn't harm - especially considering that I am fermenting to a lower gravity than I normally would with a beer. Certainly something I'll use next time (I added calcium sulfate to help the mash i any case). However I suspect the main culprit behind the smell was the lack of any kind of boil pre-fermentation. It's well documented that lactobacillus (among other things) are naturally present on malt (some sour beer homebrewers use malt as a source of lacto for souring their beer), and they are also well known to produce butyric acid in the presence of oxygen (those same brewers purge the headspace of their fermenters with CO2 to avoid butyric acid).

I knew this was a likelihood going into the fermentation - but I figured the trade-off of a bad smell, was the increased conversion of the grain (and higher alcohol yield), and am guessing that at some level the 'wild' side of the fermentation contributes something to the character of the final product. Otherwise why ferment on the grain, instead of say an overnight mash, then sparging/straining the grain out and boiling the wort (out of interest, I might actually try this out). A common thing I've read is that fermentation on the grain adds something to the character of the whisky.
Cristi wrote:fermentation should take a couple of days instead of weeks
To be clear, fermentation was probably done way before the point at which I started stripping. I had several reasons for leaving it for so long; (1) I wasn't initially in a hurry, as I wanted to wait for hot plate to arrive, (2) with 5kg of grain taking up 1/3 to 1/2 of the fermentor I wanted to give the yeast time to reach everything that might be trapped within the grain bed, (3) conventional homebrewer knowledge suggests there are some gains to be had leaving the yeast plenty of time to clean up secondary metabolites and produce a bit more alcohol (e.g. from diacetyl), (4) I wanted to give the stinky butyric acid some time to esterify with the alcohol into something less offensive (which it did, producing the overripe feijoa smell).

Thanks for your feedback!
NZDamon
Novice
Posts: 16
Joined: Fri Jul 28, 2017 5:06 pm

Re: AG mash (Jimbos) and stripping runs

Post by NZDamon »

So I finally got around to doing my spirit run this weekend past, and as bilgriss suggested it was a lot easier without the foaming agents in the mash causing puking.

I charged the still with about 5L of 20% low wines (a bit lower ABV than the expected 5L of 30%, possibly because I stripped a bit into the tails as I've read suggested in Jimbos AG thread and here). I heated it quickly up to just below 70C, then turned it right down, attached the head and got the cooling water running. It started off nice and gently, and I discarded an acetone-heavy 50ml worth of fores (possibly playing it a bit safe there).

Then as a bit of a learning exercise, I collected 50ml cuts in a bunch of new test tubes I have for yeast collection/maintenance - 24 all up (the idea being I can go through them to taste/smell, and try to get an idea of how I should be making my cuts in subsequent runs). That 1.2L was probably most of my heads/hearts, but I continued to collect 5 more jars of about 200ml each, from 42% (tasted like sour tails starting to come through) down to about 10%, well further than I needed to - more as a learning experience than anything. But then from start of collection to end, it probably only took me an hour - quicker than I expected but possibly the side effect of running a very small still?

Anyway now I just need to sit down and do some sensory analysis on my cuts, and figure out what I want to keep and what goes into feints.
Post Reply