Kieselsol and Chitosan Test Results

updated 10/11/2023

June 2023

In October 2021, I was unable to purchase grapes, so elected to purchase Finer Wine Kits (FWK) Forte kits to fill my two barrels, both 54 liter (14.25 US gallons). I purchased three Super Tuscan kits for barrel #1 and one each Merlot, Petite Sirah, and Syrah (AKA Rhone) kits for barrel #2. The original plan was to make a blend of Italian grapes and a Southern Rhone blend, and this was as close as I could get with kits.

With kit wines, I normally use the kieselsol and chitosan (K&C), fining agents to quickly clear the wine, which are included by the kit vendors. However, these kits would be bulk aged a year, so I opted to not use the fining agents. Essentially the wines started in October 2021 would be bottled in November 2022, when the new wines are ready for barrel.

The Experiment

Two months prior to bottling, I decided to conduct an experiment. There is a lot of available information regarding most fining agents, but I’ve found little regarding K&C. So I decided to determine a few things for myself. We bottled most of both barrels, reserving 19 liters (5 US gallons) of each wine, which were treated with K&C and put in 19 liter carboys. The wines settled for three weeks, after which they were racked and bottled.

Wine Started Unfined Bottled Fined Bottled
Rhone 11/13/2021 11/05/2022 11/27/2022
Super Tuscan 11/17/2021 11/05/2022 11/27/2022

The wines were bulk aged nearly 12 months before bottling, and bottle aged nearly 7 months before tasting.

Note: In thinking about the experiment, I realize there are some important points to consider:

  • The wines are not young wines. Each batch was approximately 12 months old, so the wines had already gone through all the early aging that red wine does during the first year. While wine continues to age as long as it exists, the more rapid initial changes were complete.
  • The comparison for each wine is not between two similar batches. Each wine was one batch, aged 12 months, up to the point where the main part of the batch was bottled and the remainder treated with K&C. The K&C wines were bottled 3 weeks later, so the fined and unfined versions are as identical as possible.
  • The fraction of each batch that was fined included wine from the bottom of the barrel, on top of the thin layer of sediment. My practice is to rack the barrel down to about 3 bottles-worth remaining, bottled it, then drain off the last bit and let it clear in the fridge. However, at each topup, I use a drill mounted stirring rod to gently stir each barrel, swirling up the sediment and making the wine homogeneous. I was doing this up to 2 months before bottling (which gives the sediment time to settle before final racking), although this year I’m stopping the stirring 4 months ahead. While it’s possible the wine nearest the sediment absorbed more flavors from it, at this time I don’t believe it a significant factor.

First Round of Testing

Taste Test #1 – 06/16/2023

This past weekend my brother was visiting, so we conducted the first taste test. I opened one bottle each of the Rhone blend, fined and unfined. I poured us each a glass of each, using an aerator (which I often use for red wines). The wines were distinctly different.

The fined wine has a lot less nose (aroma); it wasn’t bad, it was just lacking in comparison to the unfined wine.

The fined wine tasted good, but in comparison to the unfined, it exhibited a bitter note. On its own it wasn’t a lot of bitterness, but when compared to the unfined wine, the fined wine was distinctly bitter.

We discussed our result, and my brother asked if the glass shape might make a difference with the nose. I have  lot of winery glasses, and not all are the same shape. But I have a box of crystal tasting glasses, so I got them out and we re-did the test.

Taste Test #2 – 06/16/2023

The tasting glasses are smaller and shaped for aroma. In the photo the tasting glass is on the right — it’s smaller and evenly shaped.

wine glass and tasting glass

This time we poured 4 samples:

  • Fined Wine – Unaerated: FU
  • Fined Wine – Aerated: FA
  • Unfined Wine – Unaerated: UU
  • Unfined Wine – Aerated: UA

We tasted the wines, eating neutral crackers in between to cleanse the palate. We compared in all combinations, to ensure we were making fair comparisons. The result was that the fined wine, aerated or  not, had LOT less aroma. Very muted. What was there was good, but there wasn’t much of it.

The bitterness was exhibited in both of the fined samples, but when aerated, it was slightly more prominent. So we ranked the samples from 1 to 4, with one being the favorite. We were in agreement of our rankings.

  • 1 – UA
  • 2 – UU
  • 3 – FU
  • 4 – FA

The unfined wine was best, with the aerated being #1. Conversely, we liked the fined aerated least. [Most red benefit from aeration or may be neutral, some few are lessened; this is one of those.]

Taste Test #3 – 06/16/2023

Right after that my elder son arrived, so we poured 4 samples for him, and he did the testing without input from my brother and me. His sensory evaluation was identical to ours, e.g., lessened aroma and heightened bitterness in the fined wine. What was different was his ranking. His order was:

  • 1  – FA
  • 2 – FU
  • 3 – UA
  • 4 – UU

He liked the fined wine better. We attributed this to his taste buds being 30+ years younger, and that he prefers more bitterness in foods and drink.

Taste Test #4 – 06/17/2023

The final test was the following night, when my brother and I opened fined and unfined bottles of the Super Tuscan.

We conducted the same test with 4 samples of wine and had the same sensory result — the fined wine had less aroma and more bitterness. Our ranking was:

  • 1 – UU
  • 2 – UA
  • 3  – FA
  • 4 – FU

We swapped the top 2 and bottom 2, but the fined vs. unfined remained the same — the unfined wine was better.

Interim Conclusion

My conclusion (so far) based upon this limited test is that the usage of kieselsol and chitosan strongly affects wine in a negative fashion, reducing the aroma and introducing bitterness in the flavor.

Please note the fined wines are not unpleasant to drink, but in direct comparison to the unfined wines, are noticeably lesser.

Going forward, I do not anticipate using K&C unless in a circumstance where a wine refuses to clear and K&C is preferable over other options.

Follow-On Taste Testing

Taste Test #5 – 06/18/2023

I had a glass of the Rhone fined wine. It is good tasting, but there is definitely a bitter note and it’s a bit acidic, something not evidence in either unfined wine. Drunk with a bit of Gouda cheese, it’s fine.

Taste Test #6 – 07/08/2023

Fred (mainshipfred on WineMakingTalk) hosted a tasting in Chantilly VA, and attendees included  Beth (VinesNBines) & David, Eric (Cynewulf), Kelly (kvaden), & Greg (berrycrush), my brother. We tasted the fined and unfined version of my Rhone and Super Tuscan, plan numerous wines brought by the other attendees.

My brother’s takeaway is that he likes Chambourcin and Marquette, neither of which he had heard of before. He was a winemaker in the very distant past, and drinks primarily Cabernet Sauvignon and Merlot in recent years, so liking Chambourcin and Marquette enough to mention it several times is actually surprising.

My summarized notes of tasting my wines:

Super Tuscan

  • unfined is “more”, meaning it has more oomph than the fined
  • fined is subdued
  • fined has evidence of volatile acid and bitterness, while the unfined is fruity
  • unfined is fruitier
  • fined displays more alcohol flavor

Overall, the unfined Super Tuscan was preferred.

Rhone Blend

  • fined displays more bitterness, while one person thought the unfined more bitter
  • unfined displayed oxidation, preferring the fined
  • conversely, someone else thought the fined displayed oxidation
  • one person preferred the fined, while another preferred the unfined
  • fined was subtle

Opinions on the Rhone Blend were very divided.

I found the Super Tuscan fined was more bitter, as I noted in my first tasting notes, but the Rhone was less distinct.

Taste Test #7 – 07/10/2023

A few days after the tasting at Fred’s shop, my niece tasted the wines.

Super Tuscan

  • Unfined has a much stronger nose
  • Fined is definitely more bitter

Rhone Blend

  • Unfined has more grape flavor and stronger nose
  • No difference in bitterness

Overall, her reactions agree with the tasting at Fred’s shop. The Super Tuscan is more clear cut, while the Rhone Blend is less distinct.

Interim Conclusion

The tasting at Fred’s shop was when the wines were 20 months old, and had been in the bottle 9 months.

One person opined that the Super Tuscan might be a 10 year wine, meaning it might have a 10 year lifespan. That may be true, and it does indicate that the wines are still young. I plan to conduct more testing in another year or so, to see if age has any effect upon the aroma and taste.

My conclusion regarding the usage of kieselsol and chitosan is unchanged. These fining agents work well, but they affect wine in a negative fashion, reducing the aroma and introducing bitterness in the flavor. The bitterness may fade with time, but I don’t visualize the aroma returning.

As previously noted, going forward, I do not anticipate using K&C unless in a circumstance where a wine refuses to clear and K&C is preferable over other options.

1 Response

  1. Scott says:

    Very interesting study and insight.

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