In this experiment, the use of malic acid is tested for its flavor and aroma contributions in a 4.5% ABV, carbonated, dry traditional mead fermented using S-04. The mead was fermented in one batch, then split between two identical secondary vessels and one was given the acid treatment. Other than the acid treatment, all other variables were identical. 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.

Acidity is one of the key parts of balance in a mead, alongside sweetness and tannin. While big fruit bomb meads have acid from the fruits, there is very little acid in honey and traditional musts often start at a pH of 7.0 before fermentation. In sweet traditional meads, the acid may help cut through the sweetness and provide balance. In a dry mead, it is a little less clear if acid is needed, as if carbonated, the carbonic acid provides brightness and there is little to no sweetness to cut. Does malic acid additions to a dry traditional brighten it up or dry it out, maybe both?

As far as I can tell, there is almost no research on the taste contribution of alternative acids in meads. Balance of Sour, Cook’s Science (May 2017) provides a nice summary in cocktails and summarizes some of the acids that are commonly used and why. Common acids that mead and winemakers can find and use are citric, malic, and tartaric acid which are purchased in a powder form. Typically, I use add acid to taste and use the acid that is appropriate for the fruit that I am using or to bring out a particular perception. The predominate acid in various fruits differs; citric acid is predominate in citrus fruits, i.e. lemons and limes, malic acid is predominate in apples, and tartaric is predominate in grapes. Someone really needs to do a comparison of the perception of different acids in meads.

This is a sister experiment to the Acid additions in a TANG cream soda mead. In that experiment, while not enough participants were able to distinguish between the two meads for the results to be statistically significant, all participants who were able to distinguish a difference preferred the mead treated with acid and the preferences were significant. In that experiment, positive descriptors of the mead treated with acid was brighter, more complex, cleaner, fuller and more mouthfeel. However, that was in a cheery vanilla mead and I expect the acid really helped hit the right note on the fruit character.

Personally, I sometimes use a bit of malic acid in short traditional because I am looking to brighten the mead up. However, I have pulled back on acid additions and add much less than I used too. Part of this is because I have dialed in high carbonation around 2.5 vol which does provide quite a bit of brightness. My hypothesis was that treatment with acid would brighten the mead up and lead to more perceived sweetness. This is based on evidence from the experiments to the Acid additions in a TANG cream soda mead. However, I did not have a prior on the preferences and was unsure what people would prefer.

Recipe: 4.5%, Dry Traditional Short Mead, Jan. 2021, 16.5 liters

• OG = 1.034
• 1 liter of 2020 dark, last harvest, 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 Himalayan sea salt
• 11.5 gram packet of S-04
• 0.5 grams of ascorbic acid
• 1 gram of malic acid

Treatment:

• 0.25 grams malic acid per gallon

Nith Valley late season darker honey tasting notes:

• Low floral
• Low perceived sweetness, not overtly honey like
• Muddled caramel, minerality
• Low acid
• Low mixed herbal/woody, some foamed milk (alfalfa)

Nutrients (calculated using The MeadMakr BatchBuildr):

• Recommended nutrient level is 78 ppm YAN for medium level
• Actual: 73 ppm YAN (medium level, scaled up due to high pitch rate)
  • Fermaid-K: 2.3 grams (contibuted 13 ppm YAN)
  • DAP: 4.3 grams (contibuted 60 ppm YAN)

At pitch

• Mixed honey, water, salts.
• Sprinkled yeast on top of must

Fermentation Notes

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 64.6°F, pH 7.0.
• +2 hours, fed all nutrients upfront with 2.3g of Fermaid-k and 4.3 g of DAP.
• +1 days, active fermentation, 66.6°F
• +2 days, degassed. Smells like apples. 66.1°F
• +3 days, degassed, 66.5°F , 1.012
• +4 days, 66.2°F , 1.002, smells of pear, apple.
• +5 days, 65.6°F, fermentation slowing, smells like honey, apple. 1.000
• +7 days, 65.6°F, FG 1.000. Racked into secondary. Added 0.12 g of ascorbic acid per gallon.

Secondary

• Bottled after another week to 2.5 volumes (primed with honey).

Both meads looked the same when bottling.

Water profile 

The mineral profile of the spring water, contribution of the salt additions and the final water profile was as follows.

Initial Tasting Notes

At bottling, I was a bit disappointed with the character of the mead. They had a mild lager-like aroma. There was some nice apples esters and fermented honey character, but they were slightly muddled by the slight sulfur. I attribute this to not using Go-ferm, and just replying on aerating with a wine whip instead of by shaking or using pure 02.

Triangle Tests 

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 5 participants, each completed five triangle tests, so there were 25 triangle tests completed overall. We had a good selection of mead experts and mead enthusiasts. There were one 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 when the meads were 6-8 months old.

Results

There was a significant difference between the two meads. In 18 of the 25 triangle tests, participants could identify the odd mead out. The null hypothesis that the results were from random guessing is rejected with 99.99 percent confidence. However, four of the five participants preferred the mead with acid added, and the one participant said they preferred the mead without acid “but not by much.” The null hypothesis of equal preference between the meads is unable to be rejected, which is really not that surprising at this sample size. Even if all participants preferred the mead with acid, we could only reject the null that they are equally preferred with 93.7 percent confidence. Here is a summary of the results:

I did five triangle tests and got three right. One person only got one triangle tests correct, another got 4 out of five, and two got all five triangle test correct. No time fixed effects were significant. What people described as the difference between the two meads and the percent of correct answers is shown in the table below.

In general, the tasting notes were consistent. The no acid mead was described by two participants as being more flat, and another described it as more bland. The mead with acid was described as brighter, more pop, and two others noting acidity as the difference.

Participant three thought the mead with malic acid was more apple forward, which may be due to the use of S-04 yeast, which has apple like esters, combined with the malic acid which is predominate in pomme fruits. Participant three also thought the acid mead had muted aroma and no minerality. In contrast, the same participant described the no acid mead as having some minerality and having fresh honey character. They also thought the mead with acid was dryer, whereas the mead without acid was drying on the back palate.

What’s interesting for me if that I had thought that brighter would mean more perceived sweetness, but one of the participants noted more brightness in addition to being dryer.

Conclusion

One of the most interesting outcomes of the experiment is that the meads were significantly different. Thus, treatment with malic acid is shown in sensory analysis to not be neutral. I wish I had got a few more participants to do the triangle tests, as the number was too low to show significance of the preference.

The base mead was the same that was used in Kieselsol and Chitosan in a Traditional Mead experiment. In that experiment, there was lower perceived acid from treating with Kieselsol and Chitosan and preferences were split despite being able to detected apart. I had hypothesized that the acidity of the baseline mead may have been perceived to be too high by some participants due to the added malic acid. However, the baseline mead has the same acid treatment as this experiment and the results of this experiment suggest that this was not the case. It is now more likely that it is due to just be lower aroma and flavor.

The flavor descriptors are similar to the sister experiment to the Acid additions in a TANG cream soda mead. In that experiment, all participants who were able to distinguish a difference preferred the mead treated with acid, and the preferences were significant. In that experiment, positive descriptors of the mead treated with acid was brighter. Now, there is some evidence for me that this character may not just be desirable merely in a melomel, but also in a traditional.

I have recommended the optional use of malic acid in the Short Mead Recipes. The current recommendation is for 0.5 grams per 5 gallons, whereas 1.25 grams was used here. Based on these results, I will keep this recommendation for the traditional. It would be interesting to do a bench trial on the levels of acid and the perceived differences to dial the level in. Either way, now we have some descriptors and evidence to help inform that optional call.

Peer Reviews:

The methodology comments 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, award-winning home brewer, participant. 

Peer review 1, Tim Richards, home brewer:

Nice experiment. I use .6 grams of malic per gallon and .2 grams citric for my traditional short meads. Mine usually have a starting gravity of 1.045 and I also carbonate to 2.5 volumes. I may try a side by side with more malic to see if I have a preference. I use liquid ale yeast Wyeast 1056 and I usually back sweeten to 1.008. I really enjoy your experiments. Please keep them coming.

Additional peer reviews to follow.