Dunder Age

[Brewstilla]

Anyone using dunder in their rums want to share how old of dunder they use? Here is my process that has been working great, but just curious about over all age. Have an old 5 barrel conical from our sister brewery. Filled with dunder from out first rum run, July 2020. Since then every batch we make I use enough dunder to drop my pH to where I want it. After stripping, I let the dunder cool and top my "pit" back up. It works great and the flavor seems deeper and more complex each time, but I started to think what others are doing vs my "solera" style dunder

 

[Anton]

Most interesting,  I presume you use some of your dunder pit in your fermentations? Approximate percentage?

[Brewstilla]

I do. I would say I use in the 5-10% range. I really just go by pH

[Foreshot]

So this probably should be a separate post but I think part of the reason we all do different things with our dunder process is that we don't actually know what it does. The big picture, like the 50,000 foot view yes, we have the general idea, but down and dirty, so to speak, we don't. I think if we did we have a more thorough understanding would have better dunder protocols. Is it the germy goo that makes it work? Is it bringing over the byproducts in the dunder that does it? Does it create some biological terroir? Does the season matter (like coolships in beer, or cane season in the Caribbean)?  Does fermentation time matter?

That being said I only used dunder in the before DSP times. I kept mine for a year or so then I would create a new pit and put a few cups of the previous one in there. I only used a small percent of dunder - normally a cup in 5g after 2-3 days of fermentation. Always made funky good stuff after a 14 day or so fermentation cycle. At that time frame the misses would start asking "What's that smell?".

[RumBumm]

If you want to know more about the dunder/muck pits you will have to dig deep into the innerweb vaults and read between the lines. i started my journey by reading "the great dunder thread" on the still dragon forum. there ia a lot on information there on why we use the dunder. a quick understanding on the is it makes more flavour. how it does that is a bio-chemists dreams/nightmare. being the rum junky i am, I'm chasing an old style Jamaican with lots of funk. the funk is created with dunder. basically how this works is there are lots of unfermentables in the rum wash. that is because the yeast can't break them down. this is where the yeasts dodgy cousin comes in A.K.A Bacteria! (i say cousin but that only because they are both little organisms, please don't shoot me). these guys now go about their dirty business of breaking down the unfermatables and creating the lovely esters we want in our funky rum. that's what the funk is, a high ester rum. what are esters? these are the chemical compounds that our tongues interpret as flavour. there are whole ester charts and what compound make them. all i know is that if your wash smells like vomit you have probably got lots of butanic acid. when this ages with the alcohols you gonna get that lovely pineapple note coming through. 

i have attached a file of some of the ester charts i have found.

 

[TuftedTurtle]

I have a 5 year old Pit that I use for special fermentations.  It's sealed up in a 330 gallon tote that I only open to add to and pull out off.  It's well molded over. 

For my flagship fermentations, I will use hot dunder from the still to melt some sugar for the next fermentation.  I even hesitate to call it dunder as it doesn't age.

James Davidson

Hye Rum

[Brewstilla]

Appreciate hearing that real world example. Similar set up here, but at two year mark. I'll keep on keepin on

[Obstler]

Does anyone use substrates other than molasses. Working on a demerara rum product that I want to keep a consistent funk on.

 

Does anyone add tails to their pits or would that not be a good idea? Thinking a possible acetobacter infection

[Brewstilla]

Only other thing I have tried is making a "dunder" pit out of our agave spirit stillage. Became an acetobactor bomb that I ended up dumping 

[Foreshot]

You should only get acetobacter if you have alcohol present. You'll probably have some in stillage but I would hope not much. Still - not necessarily a bad thing. Lots of documentation in the rum domain that's something they wanted for the vinegar. Not a ton but some. Vinegar will create ethyl acetate. Good for making a DOK style rum. 

I did a few Single Malt pits. Did a good job adding flavor.