The haze craze is off to the races in juicy IPAs, but the opposite is still true for meads. A crystal clear mead can be the difference between a medal and a flop at competitions. A wide range of fining agents are in the arsenal of a mead maker. Most fining agents work by attracting positively or negatively charged particulates suspended within the mead. This causes suspended particles to precipitate to the bottom of the vessel. A common practice is to use a positively charged agent, such as gelatin or Chitosan, followed by a negatively charged agent, primarily Kieselsol. The treatment will bind with proteins, yeast, polyphenols and other negatively-charged particles, and is especially effective. Chitosan has the advantage that it does not require tannins to work properly, allowing its use in meads, white wines, ciders, etc. Most home brew and wine making stores sell Kieselsol and Chitosan together, sometimes under the brand name Super Kleer.
Kieselsol and Chitosan works really, really well at clarifying meads. It can even be added right at the end of primary when the mead is all hazy and full of gunk, and will drop the mead clear in little time, allowing for clear mead in secondary with very little lees. It is also been stated that fining agents “improve the color, odor, flavor, stability and mouthfeel of the finished product – along with many additional, subtle, benefits.” However, despite all the advantages, are we losing anything other than unwanted particulates when using Kieselsol and Chitosan?
It is common to find comments, for example from my local home brew store, that Kieselsol is not recommended for red wines as it can strip color. Moreover, within mead making circles, the use of some fining agents such as gelatin have been commented to strip tannin. However, it is unclear, at least to me, if Kieselsol and Chitosan does the same. See an excellent GotMead podcast with Tom Repas for information on use of fining agents in secondary and the ability of gelatin to strip tannin. However, there is little hard evidence on adding Kieselsol and Chitosan in meads.
Interestingly, the common advice on Kieselsol and Chitosan seems at odds with the current literature on wines. A recent article in the Critical Reviews in Food Science and Nutrition provides a literature review when pertaining to wine. In summary, researchers have found that red wine color loss is only found at dosing rates that are four or more times higher than the maximum dosing rates used by home brewers. Thus, the risk to color loss may be overblown. However, researchers have found that there are significant loss in flavanols, medium-chain fatty acid ethyl esters, and terpenes in both red and white wines at common dosage rates. Moreover, Kieselsol and Chitosan have been documented to reduce both tartaric and malic acids. Finally, there is emerging evidence that Kieselsol and Chitosan may result in perception of astringency, even at low levels. These findings all suggest potential effects on flavor. Maybe this fining agent is not as neutral as commonly assumed?
Are we losing anything else in our path to clarity? Clearly, this needs to be clarified.
In this experiment, the use of a common two stage clarifying agents, Kieselol and Chitosan, is tested for its flavor and aroma contributions in a 4.5% ABV, carbonated, dry cream soda mead fermented using D-47. The mead was fermented in one batch, then split between two identical secondary vessels and one was given the clarifying treatment. Other than the clarifying treatment, all other variables were identical, and the batches were from the same ferment. Triangle tests are conducted to see if participants can correctly identify the difference between the two meads. Respondents also provided feedback on the differences perceived in the two meads.
My hypothesis was that the treatment may remove mouthfeel due to the reduction in particulates, but at the low dosage would not affect color. I had some suspicion that it would affect aroma/taste.
Recipe: 4.5%, Dry, Cream Soda Mead, Nov. 2020, 15 liters
- OG = 1.034
- 1 liter of 2020 golden wildflower Honey from Nith Valley apiaries
- 0.5 kg of creamed, organic, raw, Peace River honey
- 15 liter spring water
- 7 gallon fermonster fermentor
- 1.5 grams of calcium chloride
- 0.5 grams of gypsum
- 0.5 grams of Himalayan sea salt
- 10 grams of D-47
- 2 grams of ascorbic acid
- 3 grams of citric acid
- Chitosan 1% at 8.3ml per gallon (2.18 ml/grams per liter)
- Kieselsol at 2.5ml per gallon (0.66 ml/grams per liter)
Nith Valley honey tasting notes:
- Moderate floral
- High perceived sweetness,
- Honey comb, honey like, bees wax
Nutrients (calculated using The MeadMakr BatchBuildr):
- Low nutrient profile recommends 65.2 ppm YAN
- Actual: 82 ppm YAN (medium level, scaled up due to high pitch rate)
- Fermaid-K: 2 grams (contributed 13 ppm YAN)
- DAP: 5 grams (contributed 69 ppm YAN)
- Mixed honey, water, salts.
- Shook jug for two minutes to aerate
- Sprinkled yeast on top of must
Regular temperature, pH, gravity and aroma tests were taken. The table below summarizes the observations.
- +time 0, Mixed honey, water salts. Sprinkled yeast on must. Must is 62-63°F. Swirled after 1 minute.
- +1 hour, fed with 1g of Fermaid-k and 2 g of DAP.
- +1 day, fed with 1g of Fermaid-k and 2g of DAP. 64°F
- +2 days, degassed. Fed with 1g of DAP. 64°F. 1.024
- +3 days, degassed, 64°F , 1.012
- +4 days, degassed, 64°F , 1.002, added ~2 kg of polish sour cherries in a mesh bag warmed to 65°F
- +5 days, removed fruit, hardly any color left in fruit mush. 1.000
- +7 days, racked into 2 x 8 liter jugs. Added half a vanilla bean split down the center, 1 gram of ascorbic acid, and 1.5 grams of citric acid to each vessel. Mead dropped relatively clear quickly.
- After two weeks, added 1st stage clarifier to one jug then swirled gently
- 24 hours later added 2nd stage after 24 hours to one jug, swirled gently
- Bottled after another week to 2.5 volumes (65 grams of honey).
The meads were both pretty clear before bottling. It was not possible to tell which was more clear in secondary.
The mineral profile of the spring water, contribution of the salt additions and the final water profile was as follows.
Initial Tasting Notes
At two months old, I tasted both meads, and they seemed different. The baseline mead was really nice. It had bright fresh cherry flavor and mild vanilla. I would have liked more vanilla intensity to make it taste like a cream soda and less of a cherry mead. The fermentation was clean and had little fermentation characteristics apart from some mild malt-like yeast character. However, the mead with the clarifying treatment was slightly bitter and less well carbonated. I figure the low carbonation was due to less residual yeast in suspension. I let them sit for a while so that they both fully carbonated.
Due to Covid-19, and in consultation with statisticians, every participant was sent two bottles and completed up to five triangle tests. Participants were sent four or five experiments and knew that I was testing something around nutrient regimes, clarifying agents, and acidity levels. The bottles were labeled experiment A, B, C etc. as well as being labeled as treatment or baseline. Every participant was also sent enough identical red solo cups.
One scoresheet was filled out by each participant for each experiment. Participants were asked their experience level with meads, how blown their palate was, and their status as judges and home/professional brewers. Experience was given a value from one to five where one is first time having a mead to five being well-experienced. Palate was given a value from one to five where one is having had nothing to drink yet, and five was that they’ve already had too much (like just drank an IPA and sitting in a brewery). Participants were asked to say which mead they preferred, and just select one if they couldn’t tell the difference.
There were 6 participants, each completed five triangle tests, so there were 30 triangle tests completed overall. We had a good selection of mead experts and mead enthusiasts. There were two BJCP certified beer judges and two BJCP mead judges.
On average, people were experienced with meads and their palate was not tired. All had some experience with meads and off flavors. Basic summary statistics on the self reporting of participants experience and palate when taking the triangle tests:
All responses were collected within the same month. Tests were evaluated when the meads were 6-8 months old.
There was a significant difference between the two meads. Out of the 30 triangle tests, 20 could identify the odd mead out! The null hypothesis that the results were from random guessing is rejected with near 100 percent confidence. Moreover, all participants preferred the mead that was not clarified. The null hypothesis of equal preference between the meads is rejected with 96.8 percent confidence. Here is a summary of the results:
I did five triangle tests and got the first two wrong. It wasn’t until I noticed the flavor intensity that I got the remaining correct. Another participant got the first few correct, and the remaining incorrect. Most other participants’ incorrect responses were seemingly random, and no time fixed effects were significant. Some participants commented that the meads could be distinguished from each other relatively easily.
What people described as the difference between the two meads is summarized below. The mead that did not have the clarifier was described as more vibrant, fruitier, and better balanced. In contrast, two participants described the clarified mead as being bitter and another described the perception as astringent. That is fascinating, as astringency was noted to occur in some previous wine studies. Moreover, three participants noted muted flavor, blander and being more watery. One participant commented that they thought the treatment was additional fruit added. Thus, there does seem to be perceived differences in the level of flavor and aroma, which is consistent with some previous studies. Surprisingly, the findings align with results in the abovementioned scientific studies, and there was quite a bit of consistency in feedback across participants.
I was really surprised by how different the two meads were. I often use Kieselol and Chitosan for a quick turn around time in short meads. Likewise, I also use it in relatively clear standard meads to make sure there is no dust of yeast in the bottom of bottles over time for competitions. It always does the job of clarifying.
Now, I have more clarity that mead clarity using Kieselol and Chitosan may not be worth the price. The loss of fruit character was significant. Astringent and bitterness was added. It’s also interesting, that the often cited reduction in color intensity was absent. However, this is all consistent with some recent studies for wine.
A couple of things to note. The meads where relatively clear when I added the clarifier. I would not usually add the clarifier for such a mead if it’s for my own personal use. However, I would use it for a standard strength mead to avoid yeast dust. It would be interesting to repeat the experiment for a standard strength mead. I also use the clarifier at the end of primary since it can knock the mead clear. I wonder if the impact would be similar for a treatment at the end of primary for a much hazier mead, as there maybe more positively charged particulates to help any residual Kieselol to drop out. More testing is still needed for this. Perhaps a bench trial to see what the threshold is.
The same treatment in a traditional mead was evaluated at the same time (forthcoming). Interestingly, participants were able to detect a significant difference; however, preference was split. This may suggest that the issues may pertain to fruit meads, although it could also be due to the fact the there were more particulates in the traditional mead.
In the past, I recommended the two stage clarifier be used at the end of primary in a really hazy mead to speed the turn around time, for example for the Short Mead Recipes. Now, this comes with a caution for relatively clear fruit meads.
The comments on methods from the referees in the high versus low nutrient level experiment also pertain to the method used for this article. This includes: 1) Justin Angevaare, PhD, Statistician, author of p-value calculator and award winning homebrewer, https://onbrewing.com; and 2) Chris Kwietniowski, home brewer, participant.
Additional peer reviews to follow.
Excellent write up! Interesting results!
- Responce: Thanks Tom. I have greatly benifited from your service to the mead community. Thanks for everything you have shared with other mead makers.
Oh and if I said a fining agent had potential for removing tannins that would’ve been gelatin (not Kieselsol or Chitosan). If I said something different on that podcast then I must have misspoken.
- Responce: Oops. A previous version of this article had incorrectly stated “… in a recent GotMead podcast, Tom Repas commented that this clarifier should be used with caution as it can strip tannin but can also be used to strip excess tannin.” This has been corrected. I recommend anyone to check out this podcast as it is a wealth of information.
Peer Review 2: Ryan Dunlop, PhD, BJCP certified, award willing homebrewer, and statistics wizz.
…. shouldn’t the preference test be two sided?
For the “can we tell them apart?” question, one sided makes sense because you don’t care if you choose wrong more often than random chance. With a good design, you know that that is still random chance.
If either could be better than the other, I think two sided is better because you have two ways you can “have one more preferred than the other”. Otherwise you are kind of assuming that you know one is preferred and if the data show the opposite it’s just random chance.
- Responce: I agree. Previously, a one-sided test was used to test the preference of one mead over the other. However, since the direction of the preference cannot be known a priori, this has been changed to a two-sided test. Also, thanks to Justin Angevaare for confirming the test should be two-sided.