After 16 days of fermentation, I bottled my third batch of cider. This one was just like the last, except with the addition of 1/4 tsp of powered chestnut tannin. In theory, the tannin should make the cider more interesting (through body and “bite”), though apples are relatively high in tannin already, so it may not have been useful.
Different apple varieties vary quite a bit in tannin content, with most of the apples available in the US having relatively low levels. But, I gather that all apples, along with grapes and true berries, have high tannin levels compared to other fruit. I tend to like historical trivia, and an interesting piece that I learned while researching this topic is that high-tannin apples are use exclusively for hard cider, and most of those trees were cut down during prohibition. Now that the hard cider business is booming, there’s a shortage of cider apples and it takes a little while for new trees to grow and produce fruit. :)
It’s worth noting that tea is very high in tannins, to the point where over-extracted tea (like I use to make kombucha) is a typical example on how to “feel” what tannins are like. Tannins produce astringency, which is a physical sensation rather than a flavor. Many sources of tannins are bitter or sour, so adding tannins can also impart bitter or sour flavors. There are also different types of tannins, with different sources providing different types. Using wine as an example, the grapes are described as providing a “harder” tannin while oak barrels provide a “softer” tannin. I’m not sure what type of tannin tea adds, but since I know that tea results in flavors (and sensations) tastily compatible with kombucha fermentation, I foresee an addition of tea to a future batch of cider. Other possibilities are are: coffee, grapes, raisins, persimmon (unripe), cinnamon, or cloves. Some of these may contain substances that are antimicrobial (cinnamon and cloves do), or will otherwise interfere with the kombucha culture. Some may have strong inherent flavors (cinnamon, cloves) that would overshadow the effect of the tannin, and may be unsuitable. Those would probably be good subjects for small 1-quart experiments.
I previously mentioned that I was throwing caution to the wind by now adding any acidification or alcohol to my cider to prevent the growth of unwanted microbes. Apparently, apple juice used for hard cider is generally pH 3.2 – 3.8, which is lower than my kombucha is when I start. I didn’t check the pH of the cider I used, but the starting cider didn’t taste particularly sour, so I’m guessing it wasn’t anywhere close to that acidic. Normal store-bought apple juice (with added ascorbic acid) has a pH > 4.0 by my test, so I doubt that the cider was as acidic as typical apple juice intended for fermentation. Still, it’s probably worthwhile for me to check the pH of my starting tea/juice/etc.
Here’s what happened:
- 2 days: I didn’t measure anything, but fermentation was vigorous enough that I was able to hear CO2 bubbling. I’ve never seen fermentation happen this quickly or vigorously.
- 14 days: pH 4.0? I couldn’t detect any tartness or sweetness, but there was bit of astringency and bitterness. The cider solids seemed to be settled more compactly/solidly than the first two batches, which is an expected side effect of the added tannin. I was torn as to whether I should let it sit long enough to develop some tartness (and possibly lose more sweetness) or bottle it and add a little malic acid for sourness. I decided to let it go, and develop sourness naturally. At this point I started tasting it every 2 days.
- 16 days: still no sourness, but it might taste a bit better than it did two days ago.
- 18 days: pH 3.8, and it tasted a little sour. I bottled three quarts and left another 1.25 qt to settle and run thorough a paper filter. I let my cider-drinking child taste it, and she said it was “pretty good” plain. She thought it tasted “more sour” than batch two, but agreed with my suggestion that it might just be “less sweet”.
- 20 days: 1 quart run through a paper filter. Slightly sour, no detectable sweetness, and lightly astringent (no more than usual, less than green tea). it seems like the issue here was that there was too little sugar at the beginning, or that the sugar was consumed well before the acidity developed. Perhaps by batch 3, my scoby had a health supply of yeast, but was low on bacteria?
When I noticed how much sweetness had been lost at 14 days, I pulled off a bit and experimented with adding different amounts of molasses.
- 2 oz 14 day cider with 1/4 tsp blackstrap molasses: better, but very mild.
- 2 oz 14 day cider with 1/2 tsp blackstrap molasses: different, but not better. the molasses sweetness helps a bit, but the molasses flavor competes with the tannin.
At the 20 day point, when I bottled the last of it, I tried a couple more small sugar additions:
- 2 oz 20 day cider with 1/4 tsp blackstrap molasses: not good enough to devote a whole quart.
- 2 oz 20 day cider with 1/4 tsp honey: This is better, but it seems like it still needs something.
I’ve since used one quart of this to blend with something sweeter (and more sour), in 1:3, 1:1: and 3:1 ratios. This has provided a lot of clarity in what’s happening with the flavor here. I’m convinced that the chestnut powder threw off the flavor, though I’m not sure that it necessarily added any flavors. I can’t really discern any particular flavor I don’t like, so maybe it’s just that something is missing. I can definitely detect above-average astringency, so I’m tempted to point my finger at that, but I just can’t tell.
At this point I have two quarts left, one from day 18, and one from day 20. I haven’t decided what to do with them yet, but I’ll probably age one plain in the garage (cold for the new few months) and add hops to one. If the aging one isn’t palatable when I feel the need to drink it, I’ll probably try honey plus a bag of earl grey.
All in all, this was a successful learning experience even though the final product doesn’t taste as nice as the one before. I was able to learn more about blending, I confirmed that tannins add noticeable astringency when 1/4 tsp is added to 1 gallon, and I have a future experimental micro-batch planned to test whether tannins are increase yeast activity against a control.