The Old Copper Yeast Jug

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This past year I had my brother Shawn Stevens  of The Copper Onion design and build for me several pieces of copper distilling paraphanellia to use during historic distilling demonstrations as well as Hell’s Half Acre Hellbilly Burlesque Show events.

Amongst the pieces he designed and built was a Donna Jug or Yeast Jug as was commonly used by practical distillers in Southern Indiana as well as Kentucky. The Donna (possibly translating as “mother) was one of the most important tools and vessels of practical distillers and was used in a couple of different ways. The first was as an active yeast propagation tool and yeast dosage tool carried to and from the distillery by the distiller; Donna in one hand and lunch bucket in the other. The distiller at all times protecting, feeding, replicating, and otherwise nurturing or “mothering” the favored yeast strain of his/her distillery.
The second use of the Donna Jug was long term yeast storage and security. An auger was started with the yeast culture and placed in the jug which was then tied off to a rope or chain and lowered into a cistern or well where the cold temperatures prevented the yeast from becoming active. In the case of an emergency the jug was then removed, allowed to warm, and the yeast subsequently activated and prepared for propagation.

I am focused more on the former point than the latter alongside an old time practical methodology for making highly storable dried yeast. The methodology I outline below was given to me by one of the descendants of an old time Hoosier distilling family who learned the method from his grandfather and which has thus far worked well for me in preserving a couple of commercial strains and some captured strains from old Distilling sites in Southern Indiana. There is no doubt that the methodology does not capture pure strains of yeast and certainly would include potentially beneficial microbes/lactobacillus, but these would have been common amongst all of the old practical distillers and if managed well they add character to distilled spirits.

First we start by sanatzing everything quite obviously. For the purposes of these experiments a good boil for 15-20 minutes in water was sufficient.

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The next step is to create our auger, for my purposes a mixture of spent bourbon stillage from Spirits of French Lick (to adjust pH downward/acidify and provide dead yeast cells as a nutrient source for active yeast) and freshly made and yeasted mash at a ratio of 10/90. In the old days a lot of distillers boiled hops to drop pH and take care of potential bacterial problems but in Southern Indiana the method was almost always a 10-20% doseage of spent wine from brandy or mash from whiskey to adjust acidity.

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This I allowed to actively ferment with the valve of my jug open to the atmosphere. When fermentation began to die down in 4-5 days I renewed it by the same method as before although the fresh mash I added contained no yeast. First I dumped the contents of the jug (retaining in a separate container three cups of the slurry well mixed so as to “save” the yeast) rinsed it well and added my spent and fresh mash proportion, once this mixture dropped to 90 degrees I added back my saved slurry and allowed this mixture to ferment, ocasionally feeding a tablespoon of table sugar when I felt the fermentation was sluggish, I repeated this entire process many times over just to track the general cycle of the yeast.

Six days was about the longest I could go without renewing the ferment, a production week essentially, so a great timeframe for a distiller. After I became comfortable with the lifecycle of this strain I decided it was time to make some active dry yeast for longer term storage.

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I prepared a new ferment and got it to the height of fermentation. I then poured a bowl full of flour and added about six tablespoons of sugar to it well mixed. To this was added a well mixed sample of the actively fermenting liquid, only enough to make a typical dough like consistency to the flour. This mixture I folded in well and allowed to set in a bowl for 24 hours (covered with foil) to allow the yeast to begin their work. After 24 hours I rolled the dough as flat as I could, cut it into strips and placed in a dehydrator at 105 for 24 hours (in the old days this would have been done by air drying). After the dough was dry and crumbly I ran it through a food processor. It wasn’t quite a powder like consistency but was certainly as easily measurable as common commercially available active dry yeast.

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To test the activity of this yeast I emptied the contents of the jug, sanatized with a boil and made a new 10/90 solution. Fermentation was as rapid and active as previous experiments and I believe this will be a great way to practically preserve future yeast strains.

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These methods we’re once incredibly common and could be again with a little tweaking and a base understanding of how to increase yeast population by scaling up.  Still yet there are but a few commercial operations that do make their own yeast but they are a minority.  Home distillers would certainly do well to apply the methodology and it would be nice to see more small scale still builders develop new yeast jug designs for the potential market.

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