100% Dunder ferment test
Posted: Tue Jun 24, 2025 10:45 am
So I decided to try a Dunder experiment.
I had just over 4l of Dunder left in a 25l jack and I needed the jack to store backset, so I poured the Dunder into a Demijohn.
Once I'd strained and cold crashed my recent YLAY batch I was holding a jug of grain/yeast custard and had an idea.
Why not see if this 5th generation Dunder will be too rich to support a ferment without added water.
I dropped a hydrometer in the Dunder and it was exactly 1060.
So I added 67brix sugar syrup, stirring and testing (I've now forgotten how much syrup, stupidly!) to get to 1100 gravity and added a big slug of the yeast rich custard. Dropped in a few drips of rapeseed oil and shook it up.
Next day I was pleasantly surprised to see it was fermenting hard, literally fizzing up into the neck.
I left it a couple of days until it stopped, expecting it to have crashed, but the hydrometer reading was 1062, so I added syrup again up to 1100 and an hour later, it's now going nuts again.
Not really sure what I can do with this, and I'm not sure if I'm willing to commit a big ferment to it in case it does crash, but I'm now wondering if I should run a few 1 gallon ferments with differing sugar/molasses additions and just add these to my molasses rum ferments when I next do a rum cycle...
Anyone else have any experience of this or tried it?
Or have any suggestions on what I could do to further it as an experiment?
I had just over 4l of Dunder left in a 25l jack and I needed the jack to store backset, so I poured the Dunder into a Demijohn.
Once I'd strained and cold crashed my recent YLAY batch I was holding a jug of grain/yeast custard and had an idea.
Why not see if this 5th generation Dunder will be too rich to support a ferment without added water.
I dropped a hydrometer in the Dunder and it was exactly 1060.
So I added 67brix sugar syrup, stirring and testing (I've now forgotten how much syrup, stupidly!) to get to 1100 gravity and added a big slug of the yeast rich custard. Dropped in a few drips of rapeseed oil and shook it up.
Next day I was pleasantly surprised to see it was fermenting hard, literally fizzing up into the neck.
I left it a couple of days until it stopped, expecting it to have crashed, but the hydrometer reading was 1062, so I added syrup again up to 1100 and an hour later, it's now going nuts again.
Not really sure what I can do with this, and I'm not sure if I'm willing to commit a big ferment to it in case it does crash, but I'm now wondering if I should run a few 1 gallon ferments with differing sugar/molasses additions and just add these to my molasses rum ferments when I next do a rum cycle...
Anyone else have any experience of this or tried it?
Or have any suggestions on what I could do to further it as an experiment?