The Big Dunder Pit Thread

CothermanDistilling

I envision using the new 2L glass toy.. errr... 'tool' we got on some pilot dunder ferments as @grim pointed out in thoughts 1, 2, and 3... all I have used it for is Juniper so far, but impressed with the low hassle of 2 Liters at a time and being able to watch it...

FloridaCracker

By the time 6-12 hours has passed in my rum ferments I don't think that The Lord himself could stop the yeast. Very violent ferment. That stated, I will only use the aged dunder added to the boiler at stripping time. I may work up the nerve to add it to the wash, but not at this point.

CothermanDistilling

if you want to try it on a small scale, come visit and spend an hour...

Kapea

@grim said: I'm assuming the reason to wait 6-12 hours is to both give the yeast a head start (in case the >bacterial culture contained other wild yeasts), and to provide the Clostridium with a more desirable >environment - lower sugar content, per the Arroyo patent...

Was reading through the Rum chapter in the Alcohol Textbook, and Murtagh indicates:

It is found that the bacteria became inhibited whenever the sugars concentration of the medium was higher than about 6.0 grams of total sugars per 100 ml. of mash, or whenever the alcoholic concentration in the fermenting liquid was over 8.0 percent by volume, or whenever the pH decreased until it approached the value of 4.0.

I think also that some of the bacteria feed on the yeast's wastes, hence the head start for the yeast, so that sufficient yeast waste can be produced to sustain healthy bacterial growth. Other bacteria (e.g. acetobacters) are aerobic, alcohol eaters that cannot work until fermentation is essentially complete.

Smaug

I have a bucket in the shop for nearly two years. I've been waiting for it to turn with no such luck.

I keep it as a reminder as to why the dunder I use only takes about two weeks to prepare.

Only my opinion.

Kapea

Without a doubt, microflora varies greatly with geographic location. The trick is, I think, to find the sour spot for your location.

grim

@Smaug - What's your approach?

Smaug

Keep the spent beer locked down till it cools.

Then aerate by transferring from bucket to bucket and also to inoculate.

Lock it down to keep the critters out. They almost always get in when using a screen it seems. The mold structure simply does not need that much oxygen to bloom.

Leave in the hot garage for 2 weeks. Heat is your friend. 90 f + or- is ideal.

I'll post pics of what the best type of mold structure looks like as soon as I get to my home computer.

Smaug

This mold makes very floral dunder.

grim

Here's a like to one of @stillwagon's threads - working on culturing C. Butyricum.

Wondering if there were any other updates, thread seemed to end in a questionable way "up in the air". Only thing I would question is the amount required (2% of fermenter volume). My plan was to inoculate sterile dunder or a molasses starter, and then use the starter to inoculate the ferment at the 6hr mark. C. Butyricum should not require an incubator, but may benefit from removing some oxygen from the starter (bubble through Nitrogen or CO2.). Would be looking at 2 5 gallon starters, 1 C. Butyricum and 1 P. Shermanii. Worth noting, the main rum ester is Isobutyl Propionate - requires propionic acid, which is only a minor byproduct of the C. Butyricum fermentation. If you want to emphasize the propionate esters, the two bacteria approach might be the way to go.

My P. Shermanii should be here on Thursday, still no word on the C. Butyricum.

Here is a rough primer on the approach to batch propagate, appears to cover most of the points needed for a successful starter:

Some interesting points for the traditional dunder pit'ers too.

grim

@CothermanDistilling said: I envision using the new 2L glass toy.. errr... 'tool' we got on some pilot dunder ferments as grim pointed out in thoughts 1, 2, and 3... all I have used it for is Juniper so far, but impressed with the low hassle of 2 Liters at a time and being able to watch it...

As a thought experiment, or maybe a real one - don't distill the dunder directly, you don't have what you need for the esterification reactions to take place. You'll need to do it in the presence of ethanol. I'd say by volume, half dunder, half high proof neutral, target somewhere around 30-40% abv.

Allow it to reflux, 100% reflux, maybe an hour.

Slowly distill the fractions. Main distinguishable fraction should be a pineapple fruit bomb (ethyl butyrate).

I won't bother rambling about Fischer Esterification and Le Chatelier's principal. (The Fragrance of Rum, Isobutyl Propionate (PDF))

A second interesting experiment might be to run the reaction using the output of a stripping run instead of straight ethanol, in which case you should see more clearly definable fractions generated - methyl butyrate (from the methanol), and a number of other butyrates from the fusel alcohols. If you've got both C. Butyricum and P. Shermanii, and a full range of alcohols - based on the volatility of the esters, it should come off something like: pear, apples, pineapple, rum, banana, peach, apricot.

FloridaCracker

@grim, your second thought was what I was thinking and hadn't really read anywhere of doing it. It seems that most of what I've read had the live dunder either added to the wash or the SPIRIT run, not the stripping run. I had planned to add it to the stripping run and your idea of a very long reflux makes sense to me. I'm not quite prepared to add the live bugs to a wash but in the boiler right before stripping.

Just a thought; Would there be any benefit of leaving the live stuff in the boiler with the wash for an extended time (couple of hours, maybe overnight) before turning on the heat? Kind of give a chance to marry the two.

DocPorter

@grim if you don't mind me asking where'd you get your new buddies (C. Butyricum and P. Shermanii)?

grim

Japan for the C. Butyricum (Miyairi 588 - common probiotic supplement in Japan) and DIY Cheese website for the P. Shermanii (it's used to make the holes in swiss cheese).

grim

The microbiology and biotechnology of rum production

Graham H. Fleet and Victoria Green

Food Science Group, School of Chemical Sciences and Engineering, University of New South Wales, Sydney, New South Wales, Australia, 2052

Bacteria

Early literature (Allan, 1906: Ashby, 1907; Hall et al., 1935) as well as more recent literature (Ganou-Parfait, Fahrasmane and Parfait , 1987; Fahrasmane and Ganou-Parfait, 1998) report the contribution of bacteria to rum fermentations. However, there appears to be no detailed studies of their growth during fermentation, how they interact with the growth of yeasts and how they impact on rum quality. Species of Clostridium, Bacillus, Zymomonas, lactic acid bacteria and propionic acid bacteria have been reported to be involved. It is expected that the extent of their growth will be moderated by their tolerance of ethanol produced by the yeasts, the acidity of the medium, and their requirement for nutrients. Possibly, their contribution will be greater in slower developing ferments, such as those conducted by Schiz. pombe, where the production of ethanol is slower, and in those where the medium is enriched in micronutrients by the addition of dunder. Fermentations conducted at higher pH values (e.g. greater than 5.5) are, also, more likely to have a stronger contribution from bacteria. If they grow to significant populations in the early stages of the fermentation, they are likely to produce acids and other metabolites that could inhibit or retard the growth of yeasts. Also, they would utilize sugars, so that less would be available for conversion to ethanol by the yeasts. Consequently, by these mechanisms they could decrease the efficiency of the fermentation process ( Kampen, 1975; Lehtonen and Suomalainen, 1977). Their growth will be accompanied by the production of metabolites that impact on rum flavor, and this could be detrimental or beneficial, depending on the species which grow ( Fahrasmane and Ganou-Parfait, 1998). According to Hall et al. (1935) the growth of Clostridium saccharolyticum was necessary for the development of characteristic rum flavor, possibly through its production of butyric acid. The microaerophilic conditions of molasses fermentation are conducive to the growth of species of Lactobacillus and Propionibacterim, the latter contributing desirable propionic acid flavor to rum (Fahrasmane and Ganou-Parfait, 1998). Lactobacillus species have recently been found to be significant in the alcoholic fermentation of malted barley mash for whisky production ( van Beek and Priest, 2003; Priest, 2004), so it is not unexpected that they may grow in conjunction with yeasts during rum fermentations and have subtle influences on rum flavour.

grim

C. Saccharolyticum, C. Saccharobuyricum, and C. Butyricum are all the same thing.

grim

Here's a link to the Fahrasmane and Ganou-Parfait (1998) paper referenced above:

Microbial flora of rum fermentation media

If you want to continue to enjoy rum, I suggest you skip the part about the source of the Clostridium being fecal bacteria in the unprocessed water used for mashing.

DocPorter

That was a good article... very readable.

My main take aways were the high temperatures required for the Propionibacterium (37°C = 99°F)

Also the article puts an emphasis on Lactobacillus... Any plans to incorporate into your ferment?

grim

Same for clostridium (from the prop link above) 35-37c.

Primary ester from lactic acid would presumably be Ethyl Lactate - Tart, Buttery, Creamy, Coconut, Butterscotch. The other lactate esters (butyl, amyl, etc) all have somewhat creamy, nutty, buttery odors and flavors. - could see that some of these might be better suited for whiskies.

grim

The worse the smell of the acid, the more interesting the smell of the ester.

We're doing a round the world tour of carboxylic acids, here is the family tree:

• Acetic Acid (CH3COOH) - Acetobacter
• Propionic Acid (CH3CH2COOH) - Propionibacterium
• Butyric Acid (CH3(CH2)2COOH) - Clostridum
• Valeric Acid (CH3(CH3)3COOH) - Brettanomyces (isovaleric acid actually)
• Lactic Acid (C2H4OHCOOH) - Peddiococcus/Lactobacillus

grim

OK - Cut to the chase...

DocPorter

Your nose/tongue must be burning after developing that so quickly...

grim

I stole it, flavor scientists have done all the hard work.

CothermanDistilling

I am hungry after reading that... or thirsty...

punkin

See that slime trying to crawl out of the bucket?

It will crawl under your bed and kill you in your sleep one day. You mark my wordie wordie words.

Smaug

It's true. It crawled out, got completely over my whole face and nearly smothered me........But it still makes very floral dunder.

CothermanDistilling

@Smaug swimming from it at about 1:10

https://www.youtube.com/watch?v=oF-YVoFUjto

grim

Prepared a starter of P. Shermanii in a broth intended to mimic backset.

   1L water in 2L Erlenmayer
  40g blackstrap molasses (trace sugars)
1/8th tsp of DME (for nutrient)
1/8th tsp dry yeast (for nutrient)
trace White Labs yeast nutrient

Boiled broth for 30m to provide some basic sterilization and remove dissolved oxygen. Filled Erlenmeyer with argon gas, cooled to 90, pitched trace amount of dry P. Shermanii culture, re-filled with argon.

It's currently sitting on my hot plate at 90f.

Based on the study above, I should only need about 24hr... Did not add any trace alcohols to the broth.

captainshooch

Excellent. I'll be watching and look forward to your results :-bd

FloridaCracker

Curiosity got the best of me so I drained a little of the dunder from my middle drain. A LOT better than the layer up top. I could still smell a little of the molasses, a mild floral smell with just a small hint of sour. Not a bad smell at all. The look was kinda like a dark hot chocolate. Not much different than when it went in the barrel. If @punkin was closer, I would let him do a taste test, but alas, one was not done.