YAN Calculations

[David Violante]

The topic of figuring out YAN and what additions we may want or need to make as home winemakers has become a recent curiosity of mine, and I had inadvertently hijacked a Christmas Wine thread as the conversation moved from the recipe to yeast type to nutrient addition and figuring out YAN. Apologies to the OP... hence I wanted to start this thread to get feedback, wisdom, experience, and practicality from my esteemed colleagues...

I don't have the equipment necessary to test YAN, and there are a lot of variables that go into YAN. There's really no chart that can be made to say that a particular grape (or other fruit) has a particular YAN. Fruit changes from year to year as does soil additions, water levels, when it's picked, you name it. There are some really good articles and information by extension centers and yeast manufacturers online - all very helpful in understanding YAN and what yeast requirements are as related to a must's YAN. The next question for me was, so how can we figure this out without breaking the bank, even if just a little. @dmw_chef posted a paper related to YAN in meadmaking, that references a Scott Labs 2016 handbook with a formula for calculating YAN requirements based on sugar content. The paper is here: Advanced Nutrients in Meadmaking and does reference Wine Making Talk folks. There is a segment in the paper on how to make additions, and what Nitrogen content is in what products. Ex: Using GoFerm, Fermaid-O & K, DAP, and when.

The process goes something like this:

1. Determine initial Brix using a refractometer​

2. Determine Specific Gravity using a hydrometer​

3. Determine the Sugar in Grams/Liter (Sugar g/L = Brix * Specific Gravity * 10)​

4. Calculate Nitrogen Requirements (additions) in parts per million (ppm) based on the yeast you're using​

For Extra Low N requiring strains: Sugar (g/L) x 0.5​

For Low N requiring strains: Sugar (g/L) x 0.75​

For Medium N requiring strains: Sugar (g/L) x 0.90​

For High N requiring strains: Sugar (g/L) x 1.25​

​

Scott Labs 2020 Winemaking Handbook has a great deal of YAN information starting on page 41 and some corresponding charts based on initial brix and yeast type YAN requirements.

I'm curious about the position of this group and the experiences you all have in this regard. There's a ton more information out there and a lot of reasons to explore under/over using nutrients.

Thanks in advance... David

​

 

[sjjan]

I just got both a Vinmetrica YAN test kit as well as a CDR Winelab Junior with the ability to test for YAN. I am as well interested in this subject to see how I could improve the AF next time around without running into stressed out fermentations due to lack of nutrients.

One clue could be the pre-clearing that is done over here a lot with Bentonite just before the AF is started. They say that this might rob the juice of too much nutrients at the start of the AF already.

Interesting topic. Following along.

 

[RPh_guy]

Edit: nevermind.

 

[David Violante]

So after some searching around online, I came right back to this thread, right here, by Deezil in 2013. For some reason it didn't show up in the search on YAN. It's a great read and thoroughly explains YAN.

 

[sjjan]

So after some searching around online, I came right back to this thread, right here, by Deezil in 2013. For some reason it didn't show up in the search on YAN. It's a great read and thoroughly explains YAN.

Thanks for referring to the other thread on the topic. Very interesting read!

 

[Rice_Guy]

in part the question should be what style does one make?

I’m curious about the position of this group

* the old impression on nitrogen was do a guess on how dirty the must is (sugar free dry extract). If the fruit had a lot of solids it would ferment without any intervention. If it was a desert like dandelion wine everything is synthetic and in that case use DAP.
* before pandemic the vinters club had a talk on feeding yeast which presented the analogy that using DAP is like,, feeding candy to kids after Halloween, ... yeast love DAP but it isn’t really good for them and likely to cause problems. Organic nitrogen will always give a smoother fermentation! therefore only use Fermaid O.
* I read “The New Cidermakers Handbook”: Jolicoeur, 2013, last year which changed my assumptions on YAN. My assumptions currently follow his.
.. nitrogen management is one of the tools we have to create a naturally sweet wine without the use of potassium sorbate, by racking we can strip nitrogen when we are at 1.020 to intentionally cause a stuck fermentation at about 1.005
.. the available nitrogen depends on the ‘sugar free dry extract’ AKA ‘dirt’ in the must/ fruit, For the most part high extract corresponds with high flavor/ lower moisture and higher YAN and is a separate trait from SpG/ sugar. Old plants do better producing high extract, a dry year does better at producing high extract, not using nitrogen on the garden/vineyard promotes high extract, being in a dry year/climate promotes high extract. ,,, and high extract will be more likely to produce a contest winning wine.
.. every variety and every crop year will have a slightly different chemical make up, therefore the only way to really know nitrogen is to measure YAN.
.. we create a high demand for YAN by running higher temperatures in the primary, every strain of yeast will need less YAN at 10C than at 30C.
.. and as noted from the club organic nitrogen (dirt) is better for a fermentation than chemical nitrogen.

 

[dmw_chef]

Organic nitrogen will always give a smoother fermentation! therefore only use Fermaid O.

Disagree. Inorganic nitrogen has its place and uses.

nitrogen management is one of the tools we have to create a naturally sweet wine without the use of potassium sorbate, by racking we can strip nitrogen when we are at 1.020 to intentionally cause a stuck fermentation at about 1.005

Strongly disagree. Racking early does not strip nitrogen, it just strips a lot of the yeast biomass. Relying on a stall that's not delle limited or beyond the ABV tolerance of the yeast without stabilizing will always put you at risk of bottle bombs.

the available nitrogen depends on the ‘sugar free dry extract’ AKA ‘dirt’ in the must/ fruit,

Kinda/sorta. To my understanding overly clarified musts lack sterols and micronutrients that yeast need during the growth phase, which is the bigger issue.

 

[David Violante]

So how I understand YAN (at the moment but subject to change) is how it's written in the Scott Labs book and what Deezil write in 2013. This is just the background.

"In order to conduct a healthy and complete fermentation, yeast require minerals, vitamins, fatty acids, sterols and nitrogen. Minerals, vitamins, fatty acids and sterols are provided by GoFerm Protect Evolution™, whereas nitrogen is supplied by Fermaid O™ or Fermaid K™. If we consider the individual needs of the yeast, how much fermentable sugar is present and how much nitrogen is required by the yeast under these conditions we can tailor a program designed for success."​

-Scott Labs​

​

As I looked through the charts from Scott Labs and elsewhere, even in the determinations by the previous posting calculations above, I could see what the nutrient requirements are for yeasts based on sugar content (brix and/or SG). We have the ways then to meet those requirements using a variety of products like GoFerm, Fermaids, DAP, etc... and on a schedule optimized for yeast usage throughout their lifecycle and environmental change from sugar to alcohol under depleting resources.

What I'm missing, and maybe this is indeterminable for a home winemaker, is how to know what resources exist in a must prior to nutrient addition so as not to over- or under- supply nutrients for yeast.

Here's an example: honey is nutrient resource deficient even if used in enough volume to get a high initial brix. So, you need to add more nutrients and YAN so that the yeast are happy. Grapes, not so much but you still need to add some. Other fruit? There are a lot of factors that can change nutrient composition and YAN even from harvest to harvest (and before adding sugar and referencing a chart or doing a calculation based on yeast strain).

If I take a gallon of must from 10 pounds of crushed grapes, and that has an initial brix of 21, it will have a different YAN than a gallon of must from 1 pound of crushed grapes with enough sugar added to equal a brix of 21. But we're basing a chart off of sugar, and what yeast need to ferment it, not necessarily what resources are already there.

Am I overthinking it or is this just a factor of being a home winemaker and using experience and the help of others as your guide?

 

[Ajmassa]

Great Thread topic @David Violante
I think the nutrient analogy of:
‘fermK (or similar) = full balanced meal‘
vs
‘DAP = red bull‘
gives DAP a bad rep and deters some home winemakers from utilizing it, viewing as unhealthy. From what i’ve learned from other more experienced winemakers i agree with what was said above, that DAP definitely has its place and uses.

As far as analyzing different techniques to determine what YAN could be (based on multiple variables) there’s probably a ton of useful methods in there, but 9x out of 10 a standard nutrient protocol gets the job done. Plus those methods would still just be assumptions. Why go thru all that when ya can easily know for sure?

When investing serious $ into our grapes we want to ensure a healthy ferment and eliminate any possibilities of negative issues. Only way to know for sure is testing for it. It’s actually pretty cheap. Only $32. And you do NOT need a vinmetrica to utilize it—just a ph meter with 2 decimal places. vinmetrica yan kit. i will no doubt have this before my next ferment. —I said this same thing over the summer and regret not following through.

This past fall was the nail in the coffin. Had myself an extremely sluggish ferment, ended up abandoning my standard nutrient protocol and started step feeding nutrients daily to make sure there was enough in there to finish since it was taking so long. It did finish dry eventually and was definitely a learning experience. The rosé i also made from these Wash St. grapes however did not finish dry. (I can only assume the rosé lacked even more nitrogen & other nutrients from an already low nitrogen must via minimal maceration time)

I learned later that Washington State had an abnormally high amount of sluggish/stuck ferments this year. Had i known the YAN level i would have avoided a lot of stress potentially. Not letting this happen again.

 

[Rice_Guy]

the issue of nutrition is extremely complex and I would question with today’s technology if there are hard and fast answers, as noted the yeast suppliers are working on defining nutritional requirements,,,, if it was easy it would be done.

What I'm missing, and maybe this is indeterminable for a home winemaker, is how to know what resources exist in a must prior to nutrient addition so as not to over- or under- supply nutrients for yeast. . . . Am I overthinking it or is this just a factor of being a home winemaker and using experience and the help of others as your guide?

ex:
* in the early days of nutrition studies with purified diets they didn’t catch that zinc is an essential nutrient since there was enough in touching the galvanized cages to supply the RMD
* in the tissue culture lab at school we used extracts (coconut milk) for the media since it was easier to get a dose of unknown required enzymes/ nutrients/ hormones than creating a purified chemical soup.
* @dmw_chef above pointed out needed sterols/ other micronutrients
* we look at crop variability based on where it was grown and the specific year, as my dad stopped adding sulfur to the fields since the coal fired power plant was releasing enough that was captured in rain for crop need or the baby food folks have started to test regions of supply since some areas are showing increased arsenic in the rice crop.
* stress/ versus excess on an organism changes growth rates as immigrants to the US frequently are taller than their foreign raised parents and the richer parts of the world are suffering an obesity epidemic
* Jolicoeur in Cider Maker is suggesting a little disease in an orchard helps create higher sugar free extract which in turn does a higher quality finished fermentation.

As a home wine maker you probably will never have enough analytical tools to know the whole picture. University folks have more tools but then it gets to what is practical and as has been done with human nutritional guidelines rules were built to be safe for 95 or 98% of the population, ,,, are known to be over kill for maybe half of the population, ,,, and are believed to not cause damage if given in excess. The folks who run plug flow fermentors are most likely to discover micronutrients since they run long enough to see the unusual/ unexpected cause vs effects.
The good news is that YAN is a gross nutrient which is easy to demonstrate a deficiency in under defined conditions, however change conditions as dropping fermentation temperature and more nutrients are recycled so less is required to meet peak demand.

 

[dmw_chef]

Am I overthinking it or is this just a factor of being a home winemaker and using experience and the help of others as your guide?

IMHO, I think you are overthinking just a bit. Absent a way to measure YAN it's going to be experience and help of others.

But we're basing a chart off of sugar, and what yeast need to ferment it, not necessarily what resources are already there.

Remember that the charts are the *total* YAN you should have for a healthy ferment; it doesn't depend on how much YAN your fermentables provide, you've got to supplement the delta. I don't do a lot of work with fruit, but I'm told by a very experienced meadmaker to does work with lots of fruit is that a reasonable baseline is to assume that each lb of fruit/gal brings 25-30ppm YAN to the table. It's obviously going to differ as you say on the fruit and lots of other factors.

Personally, I think with good process the dangers of too much YAN leading to microbial instability are a little overstated. Nichola Hall from Scott seems to suggest that excess YAN will simply result in a larger colony and faster/hotter ferment:



I've sent a question in to check the validity of my interpretation.

Only $32. And you do NOT need a vinmetrica to utilize it—just a ph meter with 2 decimal places. vinmetrica yan kit. i will no doubt have this before my next ferment. —I said this same thing over the summer and regret not following through.

Interesting, I always assumed the vinmetrica yan kit needed a vinmetrica.

 

[dmw_chef]

Personally, I think with good process the dangers of too much YAN leading to microbial instability are a little overstated. Nichola Hall from Scott seems to suggest that excess YAN will simply result in a larger colony and faster/hotter ferment:


I've sent a question in to check the validity of my interpretation.

Reply:

You are almost correct, just one little part that will differ.

YAN- yeast assimilable nitrogen- is a driver of fermentation rate and cell number. The work done by Prof Sablayrolles at INRA showed that the YAN you have (at the onset of fermentation) is all used up (at least the ammonia portion) by the end of the exponential growth phase (this is approx. 1/3 fermentation). The difference between two similar starting sugars, and different YANs (low v. high) is that the high YAN (if high YAN requiring yeast is used) ferment will start faster, be warmer and have many more cells. This is why we say that irrespective of what your starting YAN is, you always want to do an add at 1/3 sugar drop for a positive rate of fermentation. Of course, the yeast will continue to take up nitrogen past this point, just inefficiently, and at the tail end of fermentation the yeast actually secretes amino acids (which is one of the reasons why some yeast are friendlier to ML than others). You will always have YAN at the end of a ferment, which is why the term nutrient desert is a misleading.

 

[David Violante]

Thank you gents, this is a lot of good information. I do tend to overthink a little, perhaps because I also want to truly understand. You know... dive in and swim under water a little before coming up for air. At some point you get to actually swimming when you combine the understanding and the experience.

@Ajmassa I think your experience is a great example. @dmw_chef here is the manual from Vinimetrica, it indicates you need either their unit or a pH meter that goes out to 2 decimal places.

I'm still working out the math, to actually understand the right additions at the right times (ppm vs g/gall etc...) Ex: 1G/Gallon of Fermaid O is actually 10.57ppm YAN. If I need 200ppm, is the math 200 / 10.57? The literature indicates using 1G/gallon twice, and 0.5G/gallon Fermaid K once. That doesn't seem to be nearly enough. I'm working on that.

By the way, great video... the graph is outstanding to me and visually explains a lot.

 

[Ajmassa]

Thank you gents, this is a lot of good information. I do tend to overthink a little, perhaps because I also want to truly understand. You know... dive in and swim under water a little before coming up for air. At some point you get to actually swimming when you combine the understanding and the experience.

@Ajmassa I think your experience is a great example. @dmw_chef here is the manual from Vinimetrica, it indicates you need either their unit or a pH meter that goes out to 2 decimal places.

I'm still working out the math, to actually understand the right additions at the right times (ppm vs g/gall etc...) Ex: 1G/Gallon of Fermaid O is actually 10.57ppm YAN. If I need 200ppm, is the math 200 / 10.57? The literature indicates using 1G/gallon twice, and 0.5G/gallon Fermaid K once. That doesn't seem to be nearly enough. I'm working on that.

By the way, great video... the graph is outstanding to me and visually explains a lot.

View attachment 69888

See?! This is what happens when ya start diving into YAN and additions based on known levels. You open up an entire world of confusion! Light years away from my comfortable “1g per 1gal” dosing! lol

Scott’s Labs seem to be really pushing FermaidO. Personally i’ve always avoided it unless making an addition later in the ferment. Anyway if you dive into that handbook (which is extremely beneficial. thank you for posting that) they basically say YAN from FermO is weighted. So you wouldn’t need to compensate 200 actual ppm but more like 40ppm. They are calling it “YAN Equivalent” . Allegedly 10ppm of FermO is actually 40-60ppm equivalent. Yet DAP & FermK “measureable” YAN & YAN equivalent are unchanged.

It’s super detailed and they really are in love with their Fermaid O it seems but i feel perfectly comfortable still using DAP and FermK for my nutrients—especially if my YAN level clocks in low. Not sure how extensive the research was but they only site one study within that handbook regarding this. As if all of this wasn’t already somewhat confusing Scott’s Lab decided to create entirely new terms (measureable YAN & YAN equivalent) to shill FermO. It’s like they want all to fall in line with FermO & pretend any other way is now wrong.

*(After living through 2020 it’s difficult to not be skeptical or question things— like this hard shift to FermO from Scott’s Lab while FermK & DAP have worked for so many for so long)

 

[dmw_chef]

I'm still working out the math, to actually understand the right additions at the right times (ppm vs g/gall etc...) Ex: 1G/Gallon of Fermaid O is actually 10.57ppm YAN. If I need 200ppm, is the math 200 / 10.57? The literature indicates using 1G/gallon twice, and 0.5G/gallon Fermaid K once. That doesn't seem to be nearly enough. I'm working on that.

There is a spreadsheet linked in the TBE paper; you can take a look at how it does the math.

 

[dmw_chef]

One more tidbit:

Question:

I hear a lot of conventional wisdom that excessive YAN supplementation can increase risk of microbial spoilage in finished wine; if I’m reading your answer correctly that is not the case?

Answer from Scott:

I think that the use of excessive YAN is overstated from a microbial spoilage standpoint as any lees aging/stirring will induce autolysis and that releases nutrients. However, you want to have sensible nutrient regimes (calculations, additions and management; so no excessive) as yeast nutrition is greater than nitrogen and the amount required is dependent upon temperature, pH, oxygen management, etc. If you push nitrogen really high then you need to accommodate with high vitamins and minerals which is challenging as how do you know how much. In addition low nitrogen requiring strains do not perform to their optimum in high YAN environments. A tailored regime is much better.

 

[David Violante]

See?! This is what happens when ya start diving into YAN and additions based on known levels. You open up an entire world of confusion! Light years away from my comfortable “1g per 1gal” dosing! lol

Yeah... I'm getting to see how complex it can be. It's really interesting though and I'm looking forward to coming up with a solution that I will understand and be very comfortable with, having peeked behind the science curtain. I read the YAN Equivalent component with Ferm-O but want to read through more of their research to better understand why they consider it a much higher equivalent. An important take-away for me is using a testing kit (like in doing SG, pH, TA, etc...) and understanding yeast more. As @dmw_chef and others say, "You take care of the yeast, they get the job done".

There is a spreadsheet linked in the TBE paper; you can take a look at how it does the math.

I'll have to check that out. I read through Deezil's calculations and they made sense until they didn't, among the variations of measurements used across the field (ppm, g/hL, gallons, g/L, etc...). I can figure out a complex medication dosage in the field at 2am in the dark and then this is like Ionic Greek.

Thank you all for your participation down this Rabbit Hole...

 

[David Violante]

@Ajmassa I'm curious about what your nutrient dosing schedule is. It sounds like you're using GoFerm, Fermaid-K and DAP. How much do you use when?

 

[user 36973]

You can measure the nitrogen content using the formol titration method. (Note that this is the same as the Vinmetrica test kits but doesn't run you $32 a pop.) If you have sufficient lab equipment and skills to measure TA, you can also measure nitrogen. This does require the use of formaldehyde which is nasty. I was able to buy it off Amazon though, go figure. It is the only item in my lab space labeled as flammable + poisonous (due to methanol) as well as carcinogenic.

Procedure here:
1) Titrate your 5ml wine sample to pH of 8.2
2) Titrate the formaldehyde you'll use to pH of 8.2 in a separate beaker
3) Add 2ml of the titrated formaldehyde to your wine sample
4) Measure initial volume of 0.01 N NaOH on your buret
5) Titrate to pH of 8.2 and measure final volume on buret
6) N (mg/L aka ppm) = (Vol of NaOH) * (Normality of NaOH) * 14 * 1000 / 5
This simplifies to N (mg/L) = (Vol of NaOH) * 28 if you are using 0.01N NaOH and a 5ml sample of wine.

One caveat, this measures all the Nitrogen not only the YAN, so it tends to over report the actual yeast-usable nitrogen content by upwards of 10%.

 

[stickman]

There are plenty of nutrient suppliers itching to sell you product, in the US you have Scott Lab, Gusmer, BSG, and Enartis to name a few, take your pick. Some information regarding YAN has been changing throughout the years, so you really have to decide what supplier or lab to trust, and use their products based on the current data sheets provided. I've been using Superfood for many years and don't intend on changing any time soon. Reducing the use of DAP is nothing new and has been suggested since the mid 80's as far as I know, probably earlier. The main issue is to not add DAP by itself, as this throws off the organic to inorganic ratio (3to1 typical) which already exists naturally in the must. Unfortunately there are times when the must YAN is so low that supplementing with organic nitrogen alone may not get the job done, so most current information still suggests using DAP combined with a complex nutrient for very nitrogen deficient musts.