The Big Dunder Pit Thread

Myles

Looking at the patent again the fermentation produces the precursers but the esterification mostly takes place during the 2 hour period of 100% reflux before the product phase starts.

It seems there is a lot of testing likely to be needed to get any desired flavour profile and probably different ways available to get simmilar results. As long as you find a method that works for you that is OK. Should be interesting.

jacksonbrown

A pretty important part of the patent is the use of yeasts other than Saccharomyces cerevisiae which seem to me to be unavailable. I've been working on something similar using spent wash inoculated with local bagasse but I'm stuck using the wrong yeasts. What's everyone else doing? Care for a group buy to get the right yeasts to get the correct symbiotic relationship going?

A while back I had a good batch of dunder going. It smelled like super fruity heads with lots of interesting volatiles going on in there. In an effort to 'improve' I corrected the pH to the Arroyo patents recommendations and a few days later it turned to vomit and diarrhea. Sounds horrid but that's the only way to describe the smell. I've bleached the fermentor that it was in a few times and I can still smell it in there. Obviously it got a bad infection but I don't think the issue was the pH adjustment so much. In the process I also filtered it and it inadvertently got a lot of aeration. My current thinking is that a bit of care to keep the dunder in an anaerobic state is a must. At the very least, don't disturb that crust and take from under it.

There are some bits and pieces here if people are wondering.

I'm temp controlling everything and pH control seems to be a big deal too along with pre-treating the molasses. I'm hoping with a switch from feedstock grade to food grade I can avoid having to pre-treat.

grim

Schizosaccharomyces? You can find S. Pombe, it's a well studied yeast. Lots of the beer guys have attempted to use it to make beers similar to the older styles of African beers (millet, etc).

PombeNet Fission Yeast Research

Not sure I'd hang my hat on that being the major factor. The Propionibacterium and Clostridium clearly play a major role in the ester chemistry.

There are just too many negative comments regarding S. Pombe fermentations, high sulfur, high acetic acid production, considered a fault in wines, etc.

If what Arroyo was really after was a high esterase producing yeast, he might not have been able to find it in a Saccharomyces at the time. Today, you might just jump right into a high ester ale yeast or something like a belgian (because we know today), but look at the gap you would have with prescribed fermentation temps. Would a traditional ale yeast of the time simply have performed too poorly in the tropics? Or not even been available or understood at the time? I believe Brett also has high esterase activity.

Based on what I've seen in the literature, the esterification process is taking place in 3 distinct locations, during fermentation, during distillation, and during aging. I've never seen anything that has implicated either of the first two steps as being the major producer. Some of the other longer chain esters, those are only produced through interaction with wood and aging.

It's the Fischer esterification process that's got me most intrigued. What this means is that from a dunder perspective, it doesn't matter if it smells like cheese, sweat, and vomit - those terrible smelling acids are the precursors to the esterification process that takes place in the still and makes pineapple, bubble gum, and tropical fruit.

grim

The other bit I've tried to deconstruct from Arroyo and some of the older texts is what is necessary, and what is not necessary (and, by the way, what did Arroyo leave out, and what did he purposely document incorrectly to throw off copycats).

In all the old texts, it seems those guys were fighting a losing battle with Acetic Acid Bacteria or Acetobacter in particular. I don't know whether it was just the fruit flies in the tropics, or terrible sanitation. It's clear that a good portion of what they were doing with acids and bases were focused on eliminating these bacteria and preserve yields on their farms. Those steps not likely useful for us.

It smelled like super fruity heads with lots of interesting volatiles going on in there. In an effort to 'improve' I corrected the pH to the Arroyo patents recommendations and a few days later it turned to vomit and diarrhea. Sounds horrid but that's the only way to describe the smell.

Not surprising, you didn't mention, but I'm guessing the pH was acidic (3-4ish) , you added lye or something to bring it up into the 5-6ish?

The smell was from the build up of esters from previous distillations and whatever possible esterification reactions were taking place in the dunder (probably not much). However, when you changed the pH, the environment was no longer prohibitive for the bacteria to reproduce and grow, so you restarted them, and they did what they do (produce the stinky acids).

But realize, without the stinky acids you will have no esters.

grim

Oh, one more bit I forgot - distilling with the yeast increases potential total esters as some esters are retained inside the yeast cell.

Yeast Esterases and Aroma Esters in Alcoholic Beverages (PDF) @ Wiley Online Library

jacksonbrown

So do you discount the symbiotic relationship between the yeast and bacteria or just believe any yeast will do it.

grim

No, I just think that the bacterial contribution of short-chain fatty acids are likely a major contributor just by themselves (or depending on how you look at it, is the first part of the symbiosis). I'm advocating pitching the two pure bacterial cultures directly into an active fermentation, so I don't know why you are saying I am discounting it. I'm not saying I know which is the important factor and which isn't, but I'll make a bet, and I'll guarantee there are dozens of other factors that nobody has even researched yet.

I'm fine with being wrong in my guess (it never stopped me from guessing again) - but I'll post the smoking gun evidence against my position:

Production of higher alcohols and short chain fatty acids by different yeasts used in rum fermentation. Faharsmane, et al, 1985, Journal of Food Science)

(Paraphrased in Distilled Spirits Vol 3): Fermentation with Schiz. pombe generally give rums with lesser amounts of higher alcohols and short chain fatty acids, but greater quantities of esters, compared with those conducted with S. cerevisiae.

And the reason I discount it is that I still feel that there were other historical factors that were in play at the time that aren't necessarily relevant today. Probably worthwhile to experiment with Schiz. pombe too, but I think if you tried it without the bacteria, you'd be let down.

grim

And I'm still waiting on the C. butyricum from Japan. I don't have any doubts that it will be as easy to culture as the P. shermanii. I should have just paid the extra few dollars and got it from a US lab supply.

FloridaCracker

So waiting for the wash to clear and all of the yeast to settle out may not be a good thing after all. I am starting to gather that the more shit that goes into the boiler the better.

Also, I'm thinking that 50 years from now people will look back and analyze "The Grim papers of 2015". My final test of any rum will be when I give some to my friend from Jamaica. He's a rum fanatic and is a much better judge than I am. If and when he says "Good shit, mon" I will know that I have a hit.

grim

Plenty of guys forgot more than I'd ever know! I'm not at all a rum expert, just somebody who is obsessed with wanting to know how everything works.

grim

Ok, got a little package in the mail today. Next step to see if we can culture a C. Butyricum starter from this Japanese probiotic product. I figured I'd give this approach as well, this stuff is cheap and relatively easy to get (other than the delay in getting it from Japan). Apparently in Japan, Clostridium Butyricum is a commonly used probiotic supplement, OTC. This is supposed to contain active bacteria. At 20 bucks usd for 600+ tablets, it could be a relatively cost effective approach compared to buying cultures from a lab supply at 100x the price.

I'll run the same starter that I used for the Propionibacterium Shermanii with a few crushed up tablets to see if I can get a culture going.

I thought this approach was interesting since this stuff is regulated as a nutritional supplement/drug product in Japan, so assuming it has a relatively good QC process. In addition, this is a specific strain of C. Butyricum that has been studied on humans in Japan, and is known not to contain the gene for the botulinism toxin.

FloridaCracker

Well, if it doesn't work out for your wash, you can always regulate your stool. :-O

grim

pH down to 5.35 this morning, down from a starting pH of 6.40. Smells like cheese.

grim

I did change the culture medium recipe slightly.

grim

pH down to 4.55 this morning. Smells like aged cheese, it's not absolutely terrible. A quick whiff you might think it is a strong aged Parmesan. Doesn't taste like much, the residual sugar from the mollasses is a bigger contributor to flavor. Based on the pH drop (acidification), surface bubbles (gas generation), and the odor matching exactly what would be expected from butyric acid (aged cheese, vomit), I say this was a success as well.

I think the C. Butyricum is even easier than the P. Shermanii, mainly because the Butyricum fermentation was quite visible compared to the Shermanii (which is much slower without dosing lactic acid).

I am not a trained microbiologist - but I have a hard time believing you need tens of thousands of dollars in lab equipment and anerobic incubators to essentially grow a bacteria exists quite happily in a muck pit/dunder pit (which is just about the complete antithesis of a sterile anerobic lab environment). Honestly, it's not too difficult to propagate either of these to make starters. I say both are successful, and I think most anybody that is willing to take some reasonable care can propagate these. If you are comfortable with making your own yeast slants, starters, etc - that knowledge is directly transferable and usable here. If you aren't - I'd say cut your teeth on the yeast before you jump into the bacteria. It's much more obvious to know when something has gone wrong with your yeast propagation.

grim

I'm going to retry the P. Shermanii - with a bit more sugar, a higher starting pH, and dosing lactic acid instead of citric to see if I can get a bit more active of a fermentation.

FloridaCracker

OK, mine is now 3 months old and I just pulled about a cup or so from the middle of the liquid. Still about the same brown color but it now has a definite floral quality with just an ever so small hint of chocolate. No taste test as this batch wasn't hatched in a flask. Didn't open the top to smell or look. I will probably be starting my next rum wash in a week or two and just might add some of this to the wash. In a 26 gallon wash, how much would you suggest? Also if I add it to the wash would I then add more to the spirit run?

Kapea

A bit off-topic: Will brown sugar work for making a silver rum? I found a cheap local source for 50# bags of the stuff - $20/50#. Not straight-from-the-mill cheap, but not a bad price.

dad

That would be a great price for my area...and yes it will be good.

FloridaCracker

I make my wash with a combination of brown sugar and molasses. Still enough molasses in the brown sugar to carry over some taste I would think.

grim

@FloridaCracker - Did you change your mind about adding it to the fermentation? If so, 1-4% is your number, based on the Arroyo patent, 1% if you are worried, 4% if you are brave, I suppose. Maybe @Smaug can chime in on his protocol if adding to wash at distillation. I'd imagine to get the same impact, it would need to be above 4%, which means greater than a gallon in your volume. Are you using backset as well?

FloridaCracker

@grim said: FloridaCracker - Did you change your mind about adding it to the fermentation? If so, 1-4% is your number, based on the Arroyo patent, 1% if you are worried, 4% if you are brave, I suppose. Maybe Smaug can chime in on his protocol if adding to wash at distillation. I'd imagine to get the same impact, it would need to be above 4%, which means greater than a gallon in your volume. Are you using backset as well?

Yes, in my wash I use 5 gallons of backset and my next run will be my 5th generation. I am changing my mind about using the aged stuff in my ferment because I feel like it is behaving so far. Right now I have the strip from Generation 4 waiting to do a spirit run on and I suppose I could add some to that as well. In a holding pattern waiting on a new still and will run it then. Does Arroyo call for the aged stuff to go in the ferment AND then again in the distillation or is it one or the other?

jacksonbrown

Why don't you read it :)

FloridaCracker

@jacksonbrown said: Why don't you read it :)

Already have. Several times but since @grim understands it better than I do, I figured that he could translate better since some of the details in the patent go over my head. It isn't a 2 paragraph, concise write up.

Any more questions for me?

punkin

What is the meaning of life, the universe and everything?

FloridaCracker

@punkin said: What is the meaning of life, the universe and everything?

It's very easy. Found here

punkin

Production of heavy bums?

Eat at maccas is the short answer.

IAlwaysThougthItWas42Punkin

Answer to the Ultimate Question of Life, the Universe, and Everything (42) @ Wikipedia

FloridaCracker

Thought everyone needed to know how to produce heavy bums. That IS the meaning of life, right?

FloridaCracker

Best I can understand from Arroyo is that this process is done from a SINGLE RUN. Nothing mentioned about a stripping/spirit run. Just a second run of the combined heads and tails for a lesser rum.

My plan is to try both methods of aged dunder in the wash as well as added to the spirit run. One thing that I find interesting is the "rest" of 12-18 hours after full reflux before final distillation. Lot of testing ahead. I will keep y'all informed as to what I find. I actually have 6 gallons of strip from my 4th generation that I can add the live dunder to and run. This will by my first test.

grim

@FloridaCracker - Yeah as far as I can tell single run - he does make reference to rerunning feints to produce a substandard product, but that's all I've seen.

Can you run full reflux? Arroyo recommends 1-2 hours.

The 12-18 hour applies to a post-fermentation hold time - prior to distillation - at least that's how I read it. I think most of us do this just because we don't have the time to just drop everything and distill.

I think the test is a fantastic idea, the two generations should be close enough to allow for a reasonable side-by-side comparison. I would err on the side of using slightly more dunder in the strip scenario than I would add directly to the fermentation.