Inka's Backset Diary

[Paulinka]

We all know that a good dunder is literally a gold mine of precious flavours and scents, and thus a very valuable asset in rum-making. What if we age backset? As I ferment and strip my AGs on grain, I accumulated a nice stash of backset, made from a very wide range of different grains and malts. Through the winter, I collected my strained backset in glass jars while they were still hot and stored them airtight. Some of them - especially those that had a good amount of rye in the grain-bill - developed a flowery-honey scent.

Parallel to this I made half-dozen of lacto-jars (yeasty sludge collected from the bottom of my fermenting tank mixed with freshly cooked corn-grist), inoculated with different artisan dairy products that had living lactobacillus in them. One showed appealing olfactory properties, a creamy sour scent, yet most of them had more of a cheesy, bitter and/or strange smell I rather not incorporate in my future spirits.

Now that there is no fear from freezing temperatures outside at night I poured those backsets together in a barrel with the aforementioned lactic starter, under a pear tree. First few days it only had an oily layer on top of the otherwise crystal clear mirrory surface, today it started webbing. Web has a shiny, metallic surface. It's alive!

Flower-yeast? Bacteries? I do not know exactly, and as far as I know it's not a huge concern as long as it does not start to sporulate and convert the nearby cities' population to brain-eating zombies, which I see less than a little chance.

Anyway, I decided to start a diary which I plan to update weekly with a photo and a smell-test.
Here we are at Week 1, smells like rye-bread, no acridity or bitterness detected, a bit on the sweet side:

Aged Backset - Week One

[pfshine]

How long you gonna let it sit for? And what kinda ferment are you gonna put it in?

[Paulinka]

I plan to use it until frost comes, and I put it in AG-mashes. As I don't have a source yet for cheap barley-flour made from dehusked barley-berries and malts are expensive, I won't make scotch-style whiskies a lot this year. Multi-grain bourbons are my goal until fruit-season. My actual ferment is a corn-millet combo, smells very floral and perfumey, it will be a nice addition to my backset-barrel.
Also I use lots of different type vintners yeasts, all give something of a unique profile.

Main reason to use aged backset is not just to acidify my mash but to recycle most flavours of the palette of grains I use over time. This way a few kilo of specialty malt goes a long way. I do not really care about having separate, stone-written style of spirits like all-rye or all-corn, I wish to have a multi-grain whiskey with the most complexity of flavours possible.

Right now the backset has corn, rye, barley, oat, white malt, buckwheat, special b malt, chocolate malt in descending amount as listed. If this experiment turns out good I have the possibility to overwinter it by putting it into the cellar until frosts gone.

[Paulinka]

Grey mold all over. I wonder that will it change and when. The barrel is open, but the weather is very cold at night, still around freezing point.

[Paulinka]

The backset's surface has a contiguous waxy layer with a metallic reflection. It smells like dark caramel and roasted grain fodder, like molasses flavoured groundbait designed for breams.

At this point I really feel tempted to mix some of it with GNS and distill to see how it goes through in a drink. As I have some (~2 liter, 70% abv) clarified spirit made from barley that's been sitting on salty eggwhites for quite a while, after syphoning it off from the bottom residues I will mix it with my aged backset to get a 35% abv "low wine" and distill it sometimes in the weekend before the cold hits.

Right now 20oC at day, 7oC at night, we have spring. Forecast tells the temperature will drop on Sunday to 12oC&1oC, then it will rise slowly again to 22oC&13oC.

[Paulinka]

Grey mold all over.

Now it is clear that it was not mold but a flor yeast veil.

[Paulinka]

Nearly a month later the lacto works perfectly well*, the backset smells like bread now with no fruit at all, only the chocolate malt is detectable. It always makes me wonder how long a little chocolate malt goes. It does not smell that awesome as it was a week ago, smells more relaxed and round. As a lot of the aged backset is evaporated in the open barrel - and we are still very far from the hot summer, - I topped it up with 22 liters of new backset came from the 50% corn + 50% millet experiment. First photo is taken before pouring the fresh backset in, the other one is made after.

One month old aged backset

After topping up

*I have to tell that it had a bad day or two, one of our visitors thought it would be neat and clever from him to put the cap on the barrel (which was leaned at the side of it), and some slime formed on the surface until when I realized that my Precious Aged Backset can't look up to the pear tree's crown it likes sooo much. But now it's happy again in the open barrel.

[Paulinka]

Poor backset seems sick now, high ambient temperature made it smell like cheese, also some mold formed on top and has an acetic scent. Not good. Anyway, I gave it a good 15 L fresh backset made from triticale, let's see what comes out.