“Synthetic” dunder.

[Al The Chemist]

I’m experimenting with making a dunder that contains backsets and a balanced/controlled introduction of selected acids. My hope is to remove the more chaotic bacterial infection factor from the dunder acid production process. This should also help control Ph and flavor profile as I know exactly which acids are going to potentially transform into which esters during esterification.

 

I was wondering if anyone has experience sourcing and handling Butyric acid. I'd like to add it to my dunder to create ethyl butyrate (that funky pineapple note). Though I can only find products that are not rated as food grade (even though they are pure Butyric acid).   

Any thoughts about the safety and risk of using them?

[Silk City Distillers]

Your local chemical supply house.

I don't think you'll find a 'food grade' version of these things, they aren't typically food additives.  More likely that you'll see terms like ACS, USP, NF, or Reagent.  These are more commonly used to describe purity.  Not every chemical is available in every flavor, and the price will vary significantly.   You may fall off your chair when you see pricing on some of the highest grade chemicals.

You may find it to be cheaper to produce these acids yourself bacterially...  This is the foundation of the "cousins process".

You can titrate to determine your acid concentrations to be allow for adjustment/consistency.

[Al The Chemist]

I hear you on the cost. I was pretty floored as I was looking around. I can definitely produce them myself. Though I’ve found that bacterial infections can quickly get out of hand and I’ve had some mishaps with unintended cross contaminations even with pretty strict hygiene protocols. That’s why I’m trying to skip the troublesome middle man.

 

It’s good to hear I’m not missing anything by not finding food grade products. Appreciate the info!

 

[Silk City Distillers]

The option exists to ferment these bacterially using pure cultures of acids producing bacteria like Propionibacterium Shermanii, Clostridium Butyricum, and other Lactobacilli.

Shermanii is what is used to give Swiss cheese its holes.  Butyricum is butyric producing strain that does not produce botulinum toxin, often used in probiotic supplements in other countries.  Lacto needs no introduction.  I personally felt these were the 3 'safe' options that could easily be dosed into a fermentation.

In terms of sourcing acids.  Lactic is obviously the easiest, Propionic would be second, as it's used as a food preservative, Butyric probably third, as it's not necessarily used as a flavoring or additive.

Propionic and Buytric stink to high heaven.  God forbid you spill some.  Get it on your clothes or shoes, just throw them in the garbage, you will not get the smell out, or you will ruin your clothes washer (and everything else in it).  Even opening their container is going to have people looking around for vomit and rotten, spoiled food.  This is often why glass containers of butyric acid are often used by activists and rioters as stink bombs.  

 

[Bolverk]

On the hobby side I've used butyric acid from Amazon (search butyric acid high purity compound), with great success.

(I don't know if this would pass in the pro world)

It stunk for sure, but I didn't think it was as bad as everyone said. Definitely smelly gym clothes and blue cheese, but it was a tolerable funk that didn't linger that long... this very well could be the acid I sourced.

Following the Cousins process for a 1000 g/hl AA ester load you need 10% acid in your final thumper/retort, just going off some old chromatography tests I've seen butyric acid esters are at the highest 3% of the total, so I just stuck with that percentage... the good news is you dont need much.

For my test, I only wanted around 500 g/hl AA esters, so I cut the percentages down by half and it worked. I definitely got pineapple and young banana esters where I had never gotten them before. 

 

 

 

 

 

 

 

[Al The Chemist]

I'll considering trying the bacterial route again. Appreciate the info and the warnings!

[Al The Chemist]

@Bolverk, you were not kidding! 3 drops of this stuff can take down a squre block! Dealing with it felt like handling explosives. 

I ended up with 20ml Butyric acid per gallon in my wash, I have a feeling I've over done it. Any thoughts? 

 

 

[Silk City Distillers]

Acids only half the battle, you need a rich set of heavier alcohols as well.  The isoamyl alcohol esters as important as the simple ethyl esters.  Deep tails.

[Al The Chemist]

I mixed the acids with deep tails and backset (my attempt to make a non-infected muck pit). Running a test run with this at 2 gallons "muck" in a 10 gallon wash. The Butyric acid is still very dominant in the smell, hence my concern about going overboard. I couldn't find any reference to ratio so I just took a stab. 

Wash Ph was 3.8 (whcih is odd because it was the Ph of my "muck")  having a hard time adjusting to 5.0 with Calcium Carbonate. 

 

Sugar source is Panela. 

 

[Bolverk]

As slik said the heavier iso alcohols make for the best butyric esters.

I would have mixed the butyric acid into high tails around 50%. There's too much water in the low tails.

The Cousins process the first retort has low wines (low tails 30%) and in the second retort they add high wines (high tails 50%). So they take their "acid salts" (calcified carboxylic acids) previously calcified and dehydrated lees (stillage from the retorts) this is the concentrated acids. They reacidify them with sulfuric acid and add that juice to the high tails. 

For example, my runs was a 5g wash in an 8g boiler and 1l a 2.5g thumper (i only had 1 thumper). In the thumper I added 950ml of high tails at 50% with 48.5ml of aceditc acid and 1.5ml butyric acid and added sulfuric acid until the stink went away and I could smell the esters, this ended up being about 20ml if memory serves. Then let this sit for 24 hours before running. I bypassed the thumper the fores and heads.

I'm of the opinion that for this forced/artificial ester process to work it really needs to be done in a low water environment. 

I dont know what proportions of acids you want to use adding them directly to the boiler with the wash.

Do you have a small test still?

The butyric esters have a lower boiling point than the acid itself. So i wouldn't worry too much about the stink carrying over, it just may not carry that much over at all since there is still a lot of water in the boiler acting against the creation of esters. 

How do you plan on running this?

 

[Al The Chemist]

That makes sense. Also, 1.5ml of Byteric acid to 2.5g makes a lot more sense than what I did. The puke smell is still quite rough on a 10 gal wash. I unfortunately don't have a thumper. 

I plan on running a stripping run deep into the tails using a freshly passivated copper helmet with one copper plate in it. on top of that nother chamber with a copper plate (replacing the traditional copper lentil) then a dephleg to push for longer churn and contact times with the catalyzing elements. I'm going to throw a passivated copper mesh into the boiler itself as well. I'm hoping that the heat along with the reactive copper will provide enough of a catalyzing element to constitute the esters. I am actually not super interested in Isopropyl-butyrate rather more going for the ethyl-butyrate. I'm hoping some of that forms during fermentation as the ethyl alcohols are formed.

Once the stripping run is done, I plan to run a helmet + plate on the stripped run to make cuts.

I do have a test still, though its unfortunately not copper. 

Do you find sulfuric acid reduces the puke factor? 

 

[Bolverk]

Man, its real hard to say how much of the butyric esters are actually going to come through. I just don't have a ton of experience using it in this way. I once added 30ml straight to 5g of wash and a after simple double distillation got no noticeable esters in the final product.

The sulfuric acid acts as a catalyst to kickoff the esterification process. 

Let me preface with im not a chemist, so my understanding is somewhat rudimentary...

The esterification formula looks like this acid+alcohol=ester+water this formula works both left and right. so if you have esters in a high water environment the ester bonds break and you'll end up with water, acid and alcohol, but you reduce the water and the esters hold. 

All this said, I think there's just too much water in your process.

Since you don't have a thumper, I'd try adding the butyric acid mix you made to your spirit run.

[Al The Chemist]

I hear ya. I'll give it a go and post how things turn out. Appreciate all teh advice!

 

the "right to left" factor of the equasion might indeed be an issue. after some adjustmetns. I'm at about 80ml Butyric per 5 gal (X2). 

[Silk City Distillers]

Potential solutions for water impacting esterification efficiency like in a retort still would be to use a column in 100% reflux with sulfuric acid as the catalyst.  The higher concentration of alcohol as you ascend the column preserves the esters, which will be trapped in the upper stages of the column (assuming you have sufficient plates and hold up volume).

Did a few really fun experiments with Dow Amberlyst 15 esterification catalyst, packing a small column in reflux with slow takeoff.  

[Bolverk]

If you do like Slik is saying, and I agree this is really the only option in the absence of a thumper/retort, I'd run off your fores/heads first (no reflux) then go into full reflux (Fischers esterification) for an hour before taking any product off. 

In my experience if you load the column with all the esters in the beginning of the run theyll all load with your high heads and you won't want to add that back to your final spirit, but if you wait until you're just about to switch over to hearts for the Fischers esterification you'll be in a more desirable part in the run. You'll get far less of those heady acetate esters in the front this way.

[Florida Cracker]

Definitely following this. I started a thread on dunder or muck pit back in 2015 that went crazy on the StillDragon site;

https://www.stilldragon.org/discussion/1041/the-big-dunder-pit-thread/p1

Of course my version was the Wild Wild West version where you kinda got what you got with little control over it. I sent some of the original dunder to a few here who asked for it and some of that original batch is still going strong. I'm very interested to see what a "controlled" dunder would produce.

 

FC

[Bolverk]

FC, I've read that thread at least a dozen times when I was trying to wrap my head around the whole muck pit concept. Your experiments and the comments of the others on that thread were invaluable to my current understanding.

[Al The Chemist]

FC, I recall that thread well. I was following it as it was forming. It was one of my inspirations to start this “artificial pit” as I was researching the likely bacterial infections and attempting to “cut out the middle man”. Thank you for starting that thread!
 

As it stands. I’m at about 12ml of Butyric per gallon. I am already starting to smell the iso-butyrate  in the ferment. Still no ethyl-butyrate, though fermentation is really early.  
The wash also has additions of lactic, acetic, and malic.  If I can detect any of the butyrates I’ll assume the other are also catalyzing. I looked loosely into the chemistry of sulfuric as a catalyzer and it looks like the acidity itself is a pretty significant factor. I’ll dig in a bit more.
 

as for the stripping configuration. You guys recommend running the stripping in a full 6 plated reflux? I worry that will strip things down too much even if I run it hard to tails. 
 

that’s why I landed more on the helmet + 2 plate + dephleg to push for Fischer esterification after I dispose of foreshore. 
The bottom plate (pre helmet) should help with water reduction and the plate above the helmet plus the dephleg should add a “capture chamber” and control reflux. 
the helmet itself should provide a good catalyst chamber. 
 

what do you think? 

[Bolverk]

Think you'll need to add sulfuric to the wash to after its done fermenting (and you're done letting it rest no the yeast). How much to add I have no clue... i can say in a thumper you want to use about 10% of your acid volume added as the catalyst.

Acidity is a part of it but more than that, sulfuric is a strong acid (mineral acid) and it works differently than a weak acid (carboxylic: aceditc, butyric, citric, malic), a weak acid wont dissociate like the stong, so the stong acid is needed to act as the catalyst... something about the imbalance of hydrogen molecules. I don't really understand the science/chemistry enough to explain in any detail.

I think I misunderstood something, you're planning on stripping it with the helmet and 2 plates and are you going to run it again? Or is this going to be a single run? I think either way, you're not going to get a lot of butyric esters carrying through. 

I think it would almost be better to run 4 plates kind of fast in a single pass for the esters to collect on the plates (Fischer), then when you ease up on the dephleg theyll smear through the hearts.

 

[Al The Chemist]

The plan was to indeed strip then do a pot configuration cuts run. It’s a lot of added work I’d be happy to avoid. You believe a 4 plate run should be more successful? I was planning on trying on copper contact as a partial catalyst (the plates would provide some, the helmet was new at to be the main contact point). Would be great to avoid using sulfuric (it’s a nasty acid, storage song would be a worry), though if you guys haven’t had much luck with copper as a main catalyst. I might give it a go. 

[Bolverk]

According to the Cousins process both copper and sulfuric are needed. When making the juice they mix it with copper and sulfuric and let it sit for 24h hours before adding it to the final thumper.

Ive done it with just copper in the vapor path and had good results (possibly could have been better with copper in the boiler)

 

Yes, I'd do it as a single run.

What I would do, and this is just me (mostly a double pot or pot/thumper guy).

Add sulfuric to the wash 24 hours before the run. Use the 4 plates (no/minimal reflux) go low and slow through the heads, then just as heads are about to end go into full reflux for an hour, this'll collect a ton of the esters on the plates. then let the product start flowing fast to smear the esters across the whole hearts run. As you come to tails, start with a bit of reflux to hold down tails.

Grim has more experience with Fischers esterification than me, so I'd love to hear what he recommends.

 

[Al The Chemist]

What concentration of sulfuric do you use? I can source roughly 5%. But that’s still technically considered hazmat and I’d like to save the backset as dunder. With any significant concentration of sulfuric that worries me. 
 

I’ll try the single run. That makes sense. 

[Bolverk]

I use 98%, but you only need a small amount to get the desired effect. The 5% reagent stuff has too much water.

I've been think about this... if you have 12ml pg of butyric, I'd add 1.2ml of 98% sulfuric pg

You should still be able to reuse the dunder your pH isn't going to be so low that it causes any sort of safety issues. You'll just need to add more CaO (id use CaOH as you'll need far less) to create your pH buffer in the next wash. 

 

[Bolverk]

I dont know if this will pass on the professional side, but this is the sulfuric I use.

 

https://www.dudadiesel.com/choose_item.php?id=sa950

[Al The Chemist]

Appreciate the link! At this point I dont have the facilities to safely handle or store sulfuric acid at those concentrations. 

I’m going to go out on a theoretical limb. Reading more it seems like the main contribution of the Sulfuric acid is to create a more hydrophobic environment for the esters to form in a high water content wash. 

Considering I can't currently use sulfuric. I’m going to experiment with this as follows (and will let you know how it goes):

@Bolverk, I’ll use your still configuration only to replace the 2nd form the bottom plate with a helmet. 

The first plate interaction should already bring the “low wines” on that plate to 45-60% abv. I’ll rely on the hope that the sheer thermo-kinetic energy coming out of the boiler pushes though some of the heavier desired compounds into the column. Once they are there, the environment is already going to be lower in water and will hopefully promote some esterification. 

 

As you recommended, I will run hard with little reflux to pull out heads, then let the system churn in full reflux (again, hoping the desired, heavier compounds are lifted, at least, into the first plate). From there the large copper surface contact and the lower water environment should help esterification in the column, rather than the wash. 

I can see how esterification in the wash/thumper is a lot more effective as the esters are very volatile and I’d likely be pulling a lot more of them into the system during the boil.

My wash was at 3.8 Ph before buffering to 4.75 with Calcium Carbonate, so the acid potential is high. I’ll probably do an additional acid add once fermentation is complete. 

Open to any other ideas. Wish me luck! 😀