The Big Dunder Pit Thread

grim

And also, hilarious that Davoren was struggling with foaming and puking when trying to run his study in Adelaide in 1958. 60 years later, still fighting with foaming and puking.

grim

Ok here is the other one, Tummel, 1948.

P. LeH. Tummel - 1948 - Acidity Modifies Brandy Composition (PDF)

Smaug

Super interesting. Never considered the wooden boiler to be advanced technology as such. But never really took in to account the erosion a copper kettle has to endure.

Jon_o

@grim Thank you for sharing, they are very interesting readings.

Correct me if I am wrong, but this is what I gathered to improve my runs.

The Davoren research shows that lower ph increases esters. However, he mixed all the spirits into one batch and measured.

However, Tummel measured the esters separately in the heads, hearts, and tails (page 15). He also used the re-used heads and tails in future runs. The majority of the esters are concentrated in the heads. The ph adjustment had little/no effect on the hearts portion.

I personally, take very deep foreshot cuts. Therefore, I think I might have been pouring all my rum esters down the drain with the fore shots.

I'm in the middle now of holding reflux. I'll collect the heads this round in multiple small jars, and see if I can isolate any new smells.

Smaug

Consider into your thought process how a traditional retort system exploits the use of aromatics.

jacksonbrown

please :)

grim

Ok started running some lab still trials now that I've finally got the glass still setup.

First pass for the esterification/rum trials was Ethanol + Butyric Acid = Ethyl Butyrate (Pineapple Ester)

Butyric Acid purchased from a lab supply, Ethanol is commercial grain neutral spirits (95%). I wanted to test this with pure components, then I'll move on to my own washes with propagated bacteria and their acids.

250ml Ethanol 10ml Butyric Acid

No acid catalyst was used (no sulfuric acid) - I specifically omitted the sulfuric acid catalyst typically used in Fischer esterification reactions because it wouldn't typically be a component of beverage distillations. This would make the reaction yield lower, and much slower.

Also, the volume of Ethanol was in excess, I didn't want to run this reaction similar to how an organic chem lab would run it, but what would be found in a typical plated distillation. I did not use water, I will do another run with water (knowing the yield will be lower, Le Châtelier's principle, etc)

One comment on the butyric acid, it really smells like vomit. And it smells exactly like the wash innoculated with Clostridium Butyricum. That was solid confirmation that the bacteria are propagating and producing what we expect them to produce.

Refluxed for one hour with the stir bar running (Allihn Condenser), than slowly collected. There was very little fractionation as the boiling flask was filled with 95% Ethanol and water. However, by the middle of the collection the distillate was smelling strongly of pineapple.

Watered down the collected distillate, 50/50, and lost some of the pineapple aroma, however the distillate strongly tasted of pineapple, fruity, sweet. Compared side by side with fresh gns, big difference.

I'm going to run it with the acid catalyst as well, to understand the difference in yield, but I was very happy to see that the esterification reactions are taking place. There was a very tiny amount of butyric acid carryover in the distillate. I could not identify it, but my wife (who should be a professional noser) was able to pick it up right away.

I left 1/3rd of the initial liquid in the boiling flask to understand how much ester would be left behind after distillation. The remaining liquid was a very strong mix of pungent vomit and faint pineapple.

This pretty much cements the theory for me, Fischer-Speier esterification is absolutely taking place in beverage distillation. The organic acid precursors in the wash (not talking about the esters created by yeasts, but the acids themselves) play a role in distillate aroma. This isn't any kind of breakthrough, lots of literature supports it, but it was really interesting to play it out. In the back of my head I was concerned that the catalyst was critical. I found some other literature that indicates that the reaction can take place via an alternative mechanism, but is slower, with lower yield.

Smaug

Nice.

I feel like your experiments performed will serve you well when it's time to really exploit the profiles your looking for when you get into your rum program.

Do you think you will ultimately supplement your rum beer with a precursor to fast track your desired aromatics?

Super cool stuff.

Thank you as always for sharing.

punkin

Great experiments all round.

FloridaCracker

Lotta info there. Thanks.

grim

Absolutely will be using the bacteria I mentioned as well as a few others I'm not going to mention. :) There are even more interesting ones.

Our own trials are showing us that the non-yeast microbiology is incredibly rich/complex, more so than the first yeast trials we ran. Dare I say, the bacteria are just as important as the yeast and grain/sugar in the final product. We've done a bunch of work, the glass lab still example above was just trying to prove out we aren't just making things up (and this is one of my favorite threads, so I want to keep it going).

Few other thoughts. Starters are critical, direct dosing doesn't provide enough of bacteria (Jon_O was right), and the starter media will need to differ from the ferment. Also, timing of the bacterial dosing is critical as well. Depending on your protocol, sterilization of your fermentation media may be required, especially if you can't step start enough bacteria to overwhelm the local population.

Arroyo was 100% correct, and the first folks who invented and used dunder pits, probably had no idea what they did or why, but they were 100% correct too.

grim

The other important finding, I think, is that those who are using dunder pits, might be seeing an impact, even if they aren't growing the right bacteria.

Through recycling of tails, you are increasing many of the non-ethanol alcohols/fusels back into the wash. These are critical for the esterification reactions. Many of the most interesting esters are going to be made with the fusel alcohols, not ethanol.

So now, I'm finally starting to understand what's going on in the thumpers of a traditional rum distillation. Exactly this - they are esterification reactors.

Smaug

Great description. I always viewed the promotion of esterfication as sort of stewing down a southern Italian styled tomato "gravy" kinda sorta.

CothermanDistilling

@grim you got a pic of your glass still setup running in reflux?

grim

I have a video on my phone. I feel that I should know how to post the thing to youtube.

But here is a pic. This was 100% reflux at startup, standing at the top of an 8' ladder. :)

punkin

I think he wants to see your lab still.

FloridaCracker

Crap! Now I have to save tails to add back to the next distillation? Shit is getting more complicated by the day.

On another note, I have cut some of the stuff that was put into the oak barrel for a month and then left to age in the jars. Was originally distilled on 8-15-15. It has lost most of the oak smell/taste and the rum flavors are really coming forward. It will only get better with more time. I open the jars about once a week and each week, less and less oak.

Nice work Grim. Clearing up some of the mysteries.

grim

Oh, hah, no. Let me snap one.

Eucyblues

@Jon_o said: Therefore is it possible to just add vinegar to the wash to improve esterification, or am i miss-understanding the process?

Interesting topic - I read through piles of stuff looking at the Lost Spirits "aged rum in 6 days" process - then I tried my backyard version of it - or part of it - I believe his 'reactor' involves decomposing oak with sulphuric acid which I didn't try as i can't get hold of any except battery acid which may have other nasties in it. Whether you believe it or not it's worthwhile doing the background reading. Essentially I read this as a Fischer-esterification process using heat, acids in the spirit and phenolics from the purposely 'damaged' oak

Anyway I heated containers of rum and whisky by floating them in my boiler - kept the temps at 75C for 1 week then did a subset for another week - I tried oaked and un-oaked samples and with reference to the subject of the post above, I also added varying amounts of malt vinegar. I was surprised that the malt vinegar did seem to make a positive difference to the results. Up to a limit beyond which the vinegar remained noticeable - I think it will dissipate with time - It also seemed to react well with some rum tails I put in the test. Obviously a big part of this is rapid extraction from the oak due to the heat - like a slow 'nuking' - but it's what goes on over time with the heating which makes it different from microwaving. I also aerated the samples at times during the tests. I am also considering using some malt vinegar in the wort and/or wash of future rum batches

I do believe this process gets ahead start on aging - maybe 12 months worth - and is better with rum than whisky - I'll try it again with rum - The results are now being monitored over time but I am drinking one batch a lot sooner than I would be able to do without this process

For those interested and who haven't yet read this stuff- I attach the Lost Spirits patents their 'white paper' and 2 review articles from Boston Apothecary

• US2014048421 SYSTEM AND METHOD FOR RAPID MATURATION OF DISTILLED SPIRITS (PDF
• US2014048421 SYSTEM AND METHOD FOR RAPID MATURATION OF DISTILLED SPIRITS-CLAIMS (PDF)
• Lost Spirits White Paper (PDF)
• Investigating Wired’s Investigation of Lost Spirits Accelerated Aging Boston Apothecary (PDF)
• Investigating Lost Spirits Investigations Part II Boston Apothecary (PDF)

FloridaCracker

Just when I thought that I had heard of everything; Very cool work, Eucy. Looking forward to your trials. Lotta thinking outside of the box on this forum and pretty much the only one I visit anymore.

grim

There are no additives per the patent, he is simply heating the spirit with wood. Ignoring the lengthy introduction, it boils down to simply heating the spirit in the presence of wood. The invention takes one line to describe:

Heat spirits in the presence of wood.

Everything else is explaining why this is the best thing since sliced bread.

[0031] Of the various advantages of the present invention, one is that no additional ingredients or acids are provided to facilitate the process. In this regard, the process is free of additives. Without being bound to any particular theory, it is thought that the inventive process rapidly extracts acids from the wood. These acids facilitate the esterification process without the need for additives beyond the wood and the unmatured distilled spirit.

Interestingly, there seems to be plenty of prior art in this case (this seems very similar to earlier patents by Kairos Corporation, who also market this as an accelerated aging product). As well as numerous academic studies and papers on the topics.

Not only that, there are good cases from the hobby community. For example, over at Modern Distiller - FullySilenced posted his Nuclear Whiskey thread on April 6, 2013 Followed by similar posts over at HD and elsewhere. Then this patent is filed a few months after? Coincidence?

(warning: I have a collection of tinfoil hats).

I'm not trying to be overly snarky here, but I ran out of coffee this morning. I'm not trying to take away from the significance of this, but it appears to be very simple. Heat spirits in the presence of wood.

First recognize this point, than read all the other content.

Jon_o

Excellent information. I was thinking of what experiments I could do this week, since my sulphuric acid is still in shipping.

@Eucyblues said: I believe his 'reactor' involves decomposing oak with sulphuric acid which I didn't try as i can't get hold of any except battery acid which may have other nasties in it.

I ordered my acid from Ebay. Sometimes it is called muriatic acid.

@Eucyblues said: Anyway I heated containers of rum and whisky by floating them in my boiler - kept the temps at 75C for 1 week then did a subset for another week - I tried oaked and un-oaked samples and with reference to the subject of the post above, I also added varying amounts of malt vinegar. I was surprised that the malt vinegar did seem to make a positive difference to the results. Up to a limit beyond which the vinegar remained noticeable -

I have all my whiskeys and rum, just aging in canning jars with some home charred oak. Was there any reason to choose 75C? I am thinking of just putting all my jars in the oven at ~75C for a few hours and see if there is any improvements.

I will also make 2 additional jars to see the impacts.

1. Rum Heads + Oak
2. Corn strip rum (Heads/Hearts/Tails) + Oak.

According to Tummel, most of the esters are in the heads. My Rum heads have a great smell, but it is one dimensional. I hope the heat+oak develops it further. For the corn jar, that is the only jar I had with some tails in it, so i thought it would give it a try. It seems Eucyblues had some good results with tails + oak + heat.

@Jon_o said: Therefore is it possible to just add vinegar to the wash to improve esterification, or am i miss-understanding the process?

For this comment, I wasn't very clear, but I was questioning adding vinegar (Acetic Acid) to the boiler during distillation (instead of sulfuric acid).

For the sulfuric acid, my further experiment will be similar to Tummels. He used sulfuric acid in the boiler to lower ph, and created more esters. For this experiment, I plan on using a double thumper still (Jamaican traditional method), and applying the sulfuric to the 1st thumper instead of the boiler. The thumper's volume is lower, so I should be able to use less and still greatly reduce the ph.

grim

You should be able to find hydrochloric acid (aka muriatic acid) at most any large hardware or paint store. It's typically used for paint prep and masonry cleaning.

Any mineral acid should work well as the acid catalyst. Sulfuric is preferred because you can adjust the pH significantly, without adding a considerable amount of additional water (which is counterproductive).

I wouldn't attempt to use any additional organic acids to adjust the pH unless you want them to become esters. Especially acetic acid, because you'll end up creating more ethyl acetate, which comes across VERY headsy and solvent.

If you were going to try this route, lactic acid might be more interesting in an aged product.

FloridaCracker

Man, without any perspective, that oak looks like railroad ties. :))

Eucyblues

@grim said: There are no additives per the patent, he is simply heating the spirit with wood. Ignoring the lengthy introduction, it boils down to simply heating the spirit in the presence of wood. The invention takes one line to describe:

Heat spirits in the presence of wood.

Everything else is explaining why this is the best thing since sliced bread.

Buried in all the guff (which I don't want to trawl through again) are referecnes to a 2 stage process and reference to some form of accelerated breakdown of the oak in the 'reactor' which he calls "splitting apart big polymer particles in the oak" . There is some evidence that the oak is heavily charred and the lignins broken down with acid to mimic aging. Pre-damaging the oak with acid would not be considered an 'additive' I feel..
There are a number of other articles on the web about phenolic esterification of oaks using acid as a catalyst..

I found some notes I wrote to a friend just after I read it all: - copy below:

It's all about esterification - and it seems (in very simple terms at least) it's a 2 stage process

Firstly (as you can read in the patent and the article) - carboxylic (pronounced carbo-silic) acids react with ethanol to form short chain esters
Phase 2 he calls 'splitting apart big polymer particles in the oak" I believe is a process called Phenolic Esterification - and it needs the chemicals produced in Phase 1 to complete the process

Of course he doesn't spell out the details - but the biggie appears to be the importance of Ethanoic Acid - known to you and I as Acetic Acid. A lot of the esterification processes rely on the presence of Acetic Acid reacting with ethanol or other compounds. So in his first stage, I believe he maximises the production of Acetic Acid - He also tries to maximise this through the fermentation and distillation stages - Once this stage is completed he blended 2 batches together (in the first iteration of his device at least) to complete the process.

Acetic acid is produced when you oxidise ethanol - this can be done by heating to 150C under reflux and high pressure - normally using a catalyst (He says he doesn't add anything - and probably not a lot of Acetic Acid is required anyway)

Davis states that his process MAY involve pressures up to 6psi - VERY INTERESTINGLY - this is the pressure you would get by heating a closed vessel from 20C to 150C - A temperature he does not claim to use - how does he get to 6psi ???? - Maybe the evaporating Alcohol will increase the pressure to that figure - more work needed...

The Phase 2 process is related to phenol and aldehyde extraction - and this is where the charred oak (and toasted) is important because charring breaks down the lignin and increases the yield of phenols, lactones etc

Bringing the 2 phases together allows the results of phase 1 act on the phenols and other compounds to create a mimic of years of ageing.

Eucyblues

@Jon_o said: Excellent information. I was thinking of what experiments I could do this week, since my sulphuric acid is still in shipping.

I chose 75C because it's mid range of the temps referred to in the patent

In terms of comparing this process to other short term heating like nuking or several hours in the oven - the esterification process takes TIME and while the heat and catalysts speed up the reactions, it's still days/weeks rather than hours. I insulated my boiler, used an STC1000 to control the temps and simply floated containers in it - It was surprisingly efficient

I don't believe it's the bees knees, but it is another tool to work with, and it did have a tastable effect on the rum

Go easy on the oak - the heat sucks a lot out of it and it's easy to overdo it - note that reiews of Davis' Rum all comment on the coke colour so he obviously lets it rip - he also sells it at barrel strength - wonder why? - see attached articles and reviews for some more info

Have fun...

• Bryan Davis Rum Diaries Blog (PDF)
• Bryan Davis - Making Rum at Lost Spirits Distillery Rum Gallery Dave Russell (PDF)

grim

The patent includes the drawings of the reactors, they consist of a pressure sensor, heating element, thermometer, and controller. Two reactors are shown, one as a stand-alone vessel and another to be inserted into a cask.

He's pretty clear that no acids are introduced. How the wood is charred is going to be incredibly important, but it's not likely he is treating the wood with acid.

You mentioned a catalyst speeding up the reaction, there are no catalysts indicated (non-mineral acid). There are actually catalysts that can increase the speed of esterification, but this patent makes no reference to those.

In my glass lab still, I can create simple ethyl esters with carboxylics, via Fischer esterification, without any catalyst, in an hour. The yield is lower than with acid catalysis, but it works pretty well.

It's easy to experiment with acetic acid. Dump a bit into the next wash you distill, the result will be incredibly obvious. Of all the simple carboxylics, acetic is the most boring.

The pressure cycling is something that's been discussed before, the theory behind it is that you can push the spirit into and pull it out of the structure of the wood. Again, if you've nuked you've seen this first hand. Nuke the spirit, seal the jar, put it in the freezer. Let it sit overnight. Break the vacuum by opening the jar, watch the wood really closely when you do it. You'll literally see tiny streams of bubbles and darker color spirit being ejected and bubbling up. However, the device described in the patent shows no mechanism for adjusting pressure.

Eucyblues

More discussion over here (if you have the energy..) - at least read goinbroke2's post on P1 for a laugh):

20 years of aging in 6 days @ HD

ChrisNZ has tried out the process (or part of it like me) and has built himself a 'reactor' - not sure if it's based on a DeLorean....

PS - I'm experimenting with the effect of 20% hydrochloric acid on the oak - there's a superficial reaction with heat but nothing useful - doesn't penetrate the body of the oak - Maybe caustic soda is worth a shot.

I reckon if Davis is (partially) breaking down the lignins and related polymers to mimic aging/degradation of barrel wood and accelerate extraction/esterification he must be using a much more industrial process than the average amateur could manage..otherwise this part of it may just be smoke and mirrors..

Recent Development in Chemical Depolymerization of Lignin A Review (PDF)

Eucyblues

Sorry all - the above is sort of off-topic for this thread - or just hanging by a thread..pun intended

To yank it back - I've ordered some Jap-Bac to try and flavour up my dunder - The question will be will it take in dunder and what's the expected lifespan ? - will it lurk in the dark ready to pounce on my unsuspecting wash, or will I have to gen it from pills each time straight into the wash ? - will be expensive if that's the case

grim

Off-topic? Heck no, right on topic.

The whole point of the bac is to increase the types and amount of carboxylic acids - propionic and butyric. One of the main points of the reactor is to increase esterification, increase longer-chain esters, etc. Absolutely related. The reactor can't react on what's not there to begin with.

I think most anyone here can use their still as a reactor. If you've got a boiler temp control, thermometer, and the ability to keep some reflux going to prevent vapor escape, you are 99% of the way there.

Even the new patent, the one that includes 420nm light (actinic, fish bulb lights, bug zapper lights, disco black lights) is absolutely doable on the hobby side.

I'm writing up a patent now that includes high power pumped IR lasers to induce these same chemical reactions through lowered activation energies. :)