High Versus Low Pitch Rate

In this experimead, a high versus low pitch rate is tested for its flavor and aroma contributions in a 9% ABV, still, off-dry traditional mead. TOSNA 3.0 was used as the baseline, and a 5 gram per gallon pitch rate was the treatment. A English ale yeast, Safale S-04 was used which is noted to have a clean flavor, a fast fermentation, and being highly flocculant. Both used the recommend 1.25 grams of Go-ferm per gram of yeast. All other variables were similar and the batches were fermented side by side. Triangle tests are conducted to see if participants can correctly identify the difference between the two meads. Correct respondents also provided feedback on the differences perceived in the two meads.

Pitch rate preferences differ by mead maker. TOSNA 3.0, recommends pitching at 1 gram per gallon for meads with starting gravity under 1.100 (and uses Go-ferm).  This contrasts with, for example, the recipes posted by Groennfell Meadery,  which recommends 5 grams per gallon (but doesn’t use Go-ferm). One area that mead makers would come across this is in online recipe calculators. For one gallon batches, The MeadMakr BatchBuildr recipe builder rounds to full packets of 5 grams and recommends the full dose of Go-ferm. Note that the calculator on Mead Made Right does not round to full packets, nor did the TOSNA 2.0 calculator that was once availbale on MeadMakr.

In the TANG nutrient profile I describe how while it may be hard to over pitch, it is possible to overpitch when rehydrating with Go-ferm. The extra nutrients from the Go-ferm when rounding to full packets is part of what is being tested in this experimead. My hypothesis was that it may affect the mouthfeel and ester profile, but I was unsure whether an off flavor from excess nutrients would be detectable.

One thing I did differently this time is let participants know what the treatment. When the triangle test for this experiment was conducted, I had participants do two other triangle test. This triangle test was the second test. Before any of the triangle tests were conducted, I told people that there would be a triangle test that compared ale yeast to lager yeast, water profiles, and pitch and nutrient rates. They did not know which test they were being served but knew it was one of the three. They were still blind to the meads in the triangle tests. The idea is to give participants a head up to the treatment which may help them zone into the potential differences, while still being blind in the triangle tests. Thus, the results should be interpreted with this in mind.

Recipe: 9%, Off-dry Standard Traditional Mead, December 2018, 1 gallon

  • 1 Gallon
  • OG = 1.068
  • 1.7 lbs Golden Toba Apiary wildflower honey
  • 29 grams Dutch Gold orange blossom honey
  • 1.2 grams of medium toast American oak.
  • 0.9 grams of medium toast French oak.
  • 0.5 grams of acid blend
  • Safale S-04

Nutrients:

  • Recommended YAN by The MeadMakr BatchBuildr for a high nutrient requirement is 206.2 YAN, medium nutrient requirement 148.5.
  • 1/3 Sugar Break: 1.046
  • 1.3g Go-ferm (40 YAN for 1 gram pitch)
  • 6.25g Go-ferm (200 YAN for 5 gram pitch)
  • 2.5g Fermaid-O (105 YAN)
  • Total Actual YAN: 145 YAN for low pitch rate, 305 YAN for high pitch rate

At pitch

  • Made an activation starter using yeast and all Go-ferm for 2 hours
  • Mixed honey and water.
  • 1 liter of distilled water and 1.5 grams of spring water.
  • Started at 65 f
  • Aerated by shaking 4 liter jug for 2 minutes.

Brewday

Fermentation

  • Degassed every 6-12 hours for first two weeks.
  • +12 h, first nutrient addition. 65f.
  • +24 h, second nutrient addition. Both at 1.066 65f
  • +48 h, third nutrient addition. Both at 1.064. Added oak. Both smelled sweet and raw honey.
  • +72 h, fourth nutrient addition.
  • +2 weeks, fermentation complete.

Secondary 

  • +1.5 months, transferred to secondary. Given two part fining agent. Cold crashed at 2 degrees C for 2 weeks.
  • +2 months, transferred to tertiary.
  • +2.2 months, took out of cold crash. Let sit at ~70 C.
  • +3 months, given acid blend, stabilized with 0.25 grams of k-meta and 0.6 grams of sorbate, given 29g of orange blossom honey.

Bottling

  • +3.5 months, bottled. Both batches were at a FG of 1.003.

Water profile 

The calculations were completed using John Palmers water profile calculator. The mineral profile of the spring water was as follows.

OrigWater

The final water profile (excluding from nutrients, etc) was as follows:

Water1g

Basically a soft water profile.

Initial Tasting Notes

This was a very good base mead. It’s a basic recipe that I would use for carbonated metheglins. The baseline mead came out really clean. Neither mead had notable alcohol or heat. There was some light fruity esters of red berry and apple. In both the nose and taste there was a citrus and floral character. For both, the floral character was dominate, but the orange blossom honey made for a more compete experience. The meads would have been more interesting carbonated or spiced. It is a good base recipe though and was nicely balanced.

Pitch rate

Difference in color and flocculation, high pitch rate on right

There were two notable differences in the meads during the process. The above picture was taken at two months after the meads were given the fining agent and cold crashed for two weeks. The high pitch rate mead had still not flocculated. This was the reason I had to use a tertiary and cold crash for another few more days after that. Uggh, it was so annoying to clear. It also came out darker. The darker color was also present after clearing the meads and in the glass.

cupstopfilled

Triangle Tests 

Tests were evaluated when the meads were 4 months old in a controlled setting with the Kingston area home-brew club, KABOB. Three triangle tests were conducted in succession. Participants were asked to identify the odd mead out in a triangle test. As mentioned participant knew that the triangle test could have been high versus low pitch rates. They completed this test second out of three triangle tests.

cups.jpg

The meads were poured 50-50 between two groups of cups that looked identical except for a sticker of a black triangle on the bottom of one set of cups. No sticker was placed on the other cup. Just over 1 oz was served in 8 oz red plastic solo cups. Randomly, half of participants were given two cups with the treatment, half were given two cups without treatment (as well as the other mead). Every participant was given the following survey sheet.

ScoreSheet

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 very experienced. Palate was given a value from one to five where one is having had nothing to drink yet to five being they’ve already had too much. If participants were correct, they were asked to say which mead they preferred and provide some comments on overall difference and presence of off flavors characteristics of the meads.

cupstop

There were 14 participants. Apparently there was a significant difference between the two meads. Out of the 14 participants, 10 were able to identify the odd mead out. A test that the results were from random guessing is rejected with a p-value of  0.004. Of the 10 that identified the odd-mead out, 9 preferred the low pitch rates, and only 1 preferred the high pitch rate yeast. A test of the preferences being equally split randomly is rejected at a p-value of  0.011. Here is a summary of the results:

data

Where the treatment is low pitch rate. More experience with meads and less blown palates was associated with higher success in the triangle tests.

summary

Experienced home brewers did slightly better than average. None of the females were homebrewers.

details

What people described as the difference between the two meads is summarized below. The high pitch rate mead was described less pleasantly. Three people thought the low pitch rate was smoother and two people thought it was cleaner. Seperate people described the high pitch rate as smelling off, having an off flavor, or bitter. Notice that no one mentioned the difference coming from esters. This makes me think that they were detecting a nutrient off flavor.

tnotes

Only one person preferred the high pitch rate. They said it had more character. One person made up their mind by just looking at the color, but said they confirmed it again by taste.

Conclusion

I was really suprised by how different the two meads were, both during the fermentation and in the triangle tests. When I first began making mead, I often made 1 gallon batches and used The MeadMakr BatchBuildr recipe builder. In those meads, I noted nutrient flavors when I used the full packets or more. It wasn’t until I did the Great Canadian Short Mead Yeast Experiment and pitched too high that it really clicked. In the TANG nutrient profile I describe how while it may be hard to over pitch, it is possible to over pitch using Go-ferm.

One of the differences between TOSNA 2.0 and TOSNA 3.0 is taylored pitch rates based on starting gravity. TOSNA 3.0, recommends pitching at 1 gram per gallon for meads with starting gravity under 1.100 whereas TOSNA 2.0, had recommeded pitching at 2 grams per gallon, at least on MeadMakr. I would be very interested to see an experiment that compares the two. What is the taste threshold, maybe 3 or 4 grams?

The extra nutrients from the Go-ferm, I think, is what was being detected by participants.  I would like to replicate this experiment, with a constant amount of Go-ferm and just differ the amount of yeast. I also liked the S-04 character compared to US-05. It is very similar to the WLP002 used in the Great Canadian Short Mead Yeast Experiment. I thought it was clean, a good fermenter, and added something to the aroma without taking away from the honey character.

Peer Review no. 1

Justin Angevaare, Statistician and homebrewer, https://onbrewing.com

What did you use for cups here? I didn’t think much of, it but then you said one person selected preference based on appearance, I wonder if participants weren’t able to differentiate the meads by appearance.

Good job randomizing the odd-out sample. This seems to be rarely done…

I’d include the detail about what type of cups were used. In the future I would mark all cups, but the odd cups in some different way. It’s possible that an aroma from the labelling method can affect results (I’m assuming permanent marker was used here – worth noting in the details). Something like a circular coloured sticker would be good in case some small amount of light makes it through the cups as well – though I doubt this was an issue here. Tricky about the meads having different appearances – not a lot you can do there unless you are blindfolding participants or something.

… Fine to use the binomial test there as well. I assuming the participants weren’t told anything further about the samples between the triangle test and the preference test. I’m also assuming particpants weren’t able to converse between the tests and preference was kept private until after results submitted/collected. Details that may be worth including.

… Is there any further detail you can provide about the self-assessment of mead exp. and palate state?

Author Responce to Peer Review no. 1

Thank you Justin for your feedback. I added information on the cups and added a picture too. I served 1 oz in 8 oz red plastic solo cups. The cups are opaque and I attached a sticker of a black triangle on the bottom of one set of the cups. I usually put a sticker of another shape on the other cups, but this is the first time I did not. You couldn’t see the stickers from the top of the glass, but participants potentially could have felt for the sticker. I will give stickers for both in the future to prevent this. 

Participants were not told anything further about the samples between the test and stating preferences. I discouraged anyone from talking about the meads out loud during the tests. I will include the survey I used that will provide more information on the meaning of palate and experience. 

Peer Review no. 2

Adam Thompson, Owner Mechalore Mead Works

Your starter is rehydrating for way too long. Does that time account for temperature stabilization with must every 15min (until within 10 C) after rehydration?

Your high end yeast pitch is way too high for this OG (you mention this). I wonder how it would compare with a higher OG or a reasonably sized yeast pitch for the high end yeast pitch.

Proponents of TOSNA say that the YAN is absorbed by the yeast during rehydration. Did you test the yeast slurry post-rehydration to see if there was any remaining YAN?

Author Responce to peer reviewer no. 2

Thank you Adam for your feedback. Regarding the starter, the two hours does account for temperature stabilization. I also feed my yeast amounts of honey as detailed in my post on Making an Activated Yeast Starter for Mead. I think of mead as its own starter. It would be interesting to do an experiment on the mead starter length. I did not test my starter post estimation for YAN as I do not have that equipment. 

I also would be very interested in testing this again in a mead with a higher starting gravity or with lower pitch rates. Good idea. 

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