scaling up a mead from a smaller recipe

[NeverDie]

Earlier in the year I did a 1 gallon BOMM but using M5 yeast, and it turned out extremely well using the nutrient amounts from the loveofroses' BOMM recipe. Now I'm nearing the end of primary fermentation on a 5 gallon mead using M5 yeast, but it's turning out that the nutrient requirements are a lot higher than a simple proportional scale-up from a 1 gallon BOMM would have been. Is this a common occurrence when scaling up, or does it indicate something else is wrong?

I say this because it started out fine but then went sulfurous. So, I gave it more nutrients and aerated. Then it was happy for about 12 hours or so, then went sulfurous again. So, I gave it more nutrients and aerated again. Then it was happy for about 12 hours or so, and it went sulfurous again. And again a third time. These extra nutrient additions and aerations are in addition to the usual stepped nutrients additions that a simple scale-up of the BOMM recipe would have called for. SG is now 1.004, so I hope this will be the last time that I have to rescue it before it ferments dry. I really hate doing fermentations by way of emergency management.

 

[Maylar]

Both Bray's BOMM recipes and the TOSNA 3.0 calculator multiply the 1 gallon requirements by 5 when scaling up. It's a grams per gallon sorta thing.

Edit: I dunno that you can assume M-05 to have the same nutrient requirements as 1388. This is why I don't use yeasts that don't specify the requirements.

 

[NeverDie]

I used different honey with the 5 gallon batch than with the 1 gallon batch. Maybe that was a mistake. OG was verified to be 1.105 by a TILT hydrometer.

Presently, pH reads 4.64 after 75 minutes of aeration with an aquarium pump. Not sure what it was before the aeration, but presumably lower due to higher CO2 concentrations then.

Tastes OK.

Anyhow, I aerated away the HS2 smell with an air stone and aquarium pump for 75 minutes, gave it more Fermaid-O, and buttoned it up. That should do it before FG is reached, but then again that's what I said the last time too.

This being my first 5 gallon batch, and by far the largest for me so far, these emergency interventions are rather nerve wracking, as I'm only guessing it wants nitrogen and not something else.

 

[Maylar]

You do know that yeast can't assimilate nutrients after 9 - 10% ABV, right?

 

[NeverDie]

Ooops. Uh, no. Didn't know that. I think I heard something like that regarding DAP, and I thought that was supposed to be an advantage of Fermaid-O: that Fermaid-O was still useful at lower SG's (higher ABV's). Do you mean to say that even Fermaid-O will be of no use in this situation?

 

[Maylar]

Yeah the organic stuff is better in that regard but not by much. The numbers I've seen say 9% for inorganic and 10% for organic nitrogen, though I wish someone would link to an authoritative source for those numbers. The current protocols say not to feed after the 1/3 sugar break which is a lot lower than that.

But, thinking about it, if it made your rhino farts go away doesn't that mean the yeast needed it?

 

[NeverDie]

Y
But, thinking about it, if it made your rhino farts go away doesn't that mean the yeast needed it?

I wish I knew. The only other explanation I can think of is that the extra nitrogen is somehow a coping mechanism for some other kind of yeast stress that's being inflicted, but that's really nothing other than wild speculation on my part.

I haven't seen any articles that say what to do when dealing with these crisis situations. Instead, they all just seem to assume perfect foreknowledge of nutrient requirements and that nothing ever goes wrong.

 

[bob1852]

But, thinking about it, if it made your rhino farts go away doesn't that mean the yeast needed it?

I'm sure bubbling an air stone through the mead for 75 minutes did more to expel the SO2 than a late addition of Fermaid-O did...

FWIW, I'd never add that much air/oxygen to a current-FG 1.004 mead....even if it did smell odd.

 

[NeverDie]

I'm sure bubbling an air stone through the mead for 75 minutes did more to expel the SO2 than a late addition of Fermaid-O did...

For sure it did, because it had expelled the the smell of HS2 even before I added the Fermaid-O, the addition of which was intended merely to avoid the production of more HS2.

What would have been a better way to handle this situation? Would the HS2 age out if I had let it stay in? I just can't abide drinking a mead that's laden with HS2, let alone sharing such a mead with friends.

 

[madscientist451]

I'm nearing the end of primary fermentation on a 5 gallon mead using M5 yeast, but it's turning out that the nutrient requirements are a lot higher

How much yeast did you pitch for the 5 gallon batch?

 

[NeverDie]

How much yeast did you pitch for the 5 gallon batch?

10 grams.

 

[NeverDie]

If it's true that the yeast can't extract nitrogen from the must above 10%, then how does the yeast meet its nitrogen needs when the ABV is above 10%? Is it drawing upon some kind of inner cellular nitrogen reserves that it built up when the ABV was lower? Or, is it accomplished some other way? In the case of yeast that ferment to 18% ABV, those reserves would have to be quite substantial.

 

[madscientist451]

The original question was about nutrient additions, but it looks like you only used 1 packet of yeast in a 5 gallon batch, which in my view, isn't enough yeast.
There are many explanations about hydrogen sulfide in fermentations, but one that I remember says adding nutrients before the yeast has had time to multiply increases the amount of hydrogen sulfide produced. There are many other factors involved besides the quantity of yeast used, but increasing the amount of yeast is one of the easiest ways of dealing with the issue.
If you get H2s early on, that can then led to other issues later.
I've heard some say that 1 packet of dry yeast per gallon of mead is the proper amount, which seems excessive to me, but it does actually work.
You can also use 1 pack in a a gallon batch and then pitch the slurry from that into a 5 gallon batch.
Other things to try: re-hydrate the yeast with go firm protect and temper the yeast before adding to the must, wait 24-48 hours before adding nutrients.
I've had a few smelly, sulfur tasting batches that I've had to dump, but I haven't had problems since I started being much more careful with the process.
Don't know if its just dumb luck or I'm just doing what works for me.

 

[NeverDie]

The original question was about nutrient additions, but it looks like you only used 1 packet of yeast in a 5 gallon batch, which in my view, isn't enough yeast.
There are many explanations about hydrogen sulfide in fermentations, but one that I remember says adding nutrients before the yeast has had time to multiply increases the amount of hydrogen sulfide produced. There are many other factors involved besides the quantity of yeast used, but increasing the amount of yeast is one of the easiest ways of dealing with the issue.
If you get H2s early on, that can then led to other issues later.
I've heard some say that 1 packet of dry yeast per gallon of mead is the proper amount, which seems excessive to me, but it does actually work.
You can also use 1 pack in a a gallon batch and then pitch the slurry from that into a 5 gallon batch.
Other things to try: re-hydrate the yeast with go firm protect and temper the yeast before adding to the must, wait 24-48 hours before adding nutrients.
I've had a few smelly, sulfur tasting batches that I've had to dump, but I haven't had problems since I started being much more careful with the process.
Don't know if its just dumb luck or I'm just doing what works for me.

Thanks! That would explain it. When I did the successful 1 gallon M5 fermentation earlier in the year, I used one full packet (10g) of yeast. However, since then other forum members have said that 2g of yeast per gallon is more than sufficient and that even 1g of yeast per gallon is actually enough, so this time around I went with 2g/gallon.

 

[NeverDie]

Maybe this also explains why loveofroses' advice is: 1 packet of dry yeast for 1 gallon and 2 packets of dry yeast for 5 gallons:

https://www.homebrewtalk.com/current-mead-making-techniques.html
It always puzzled me as to why, because it's non-proportional.

 

[NeverDie]

The original question was about nutrient additions, but it looks like you only used 1 packet of yeast in a 5 gallon batch, which in my view, isn't enough yeast.
There are many explanations about hydrogen sulfide in fermentations, but one that I remember says adding nutrients before the yeast has had time to multiply increases the amount of hydrogen sulfide produced. There are many other factors involved besides the quantity of yeast used, but increasing the amount of yeast is one of the easiest ways of dealing with the issue.
If you get H2s early on, that can then led to other issues later.
I've heard some say that 1 packet of dry yeast per gallon of mead is the proper amount, which seems excessive to me, but it does actually work.
You can also use 1 pack in a a gallon batch and then pitch the slurry from that into a 5 gallon batch.
Other things to try: re-hydrate the yeast with go firm protect and temper the yeast before adding to the must, wait 24-48 hours before adding nutrients.
I've had a few smelly, sulfur tasting batches that I've had to dump, but I haven't had problems since I started being much more careful with the process.
Don't know if its just dumb luck or I'm just doing what works for me.

It might also explain why I've had trouble nailing down the nutrient requirements for Hornindal Kveik, which I had been underpitching but nonetheless feeding nutrients from the get-go. Are there any other signals besides a 24-48 hour delay that might indicate when to add the nutrients after pitching? For example, is there a particular yeast cell density (viable yeast per milligram) that I could look for?

 

[NeverDie]

On the other hand, the default pitch rate recommended by the TOSNA calculator is 2g/gallon:
https://www.meadmaderight.com/tosna.html

I think maybe my error was adding the first traunch of nutrients up-front at the very start rather than waiting 24 hours, as recommended by the TOSNA protocol. Another error may have been not putting all the nutrients in by no later than the 1/3 sugar break.

 

[Maylar]

If it's true that the yeast can't extract nitrogen from the must above 10%, then how does the yeast meet its nitrogen needs when the ABV is above 10%? Is it drawing upon some kind of inner cellular nitrogen reserves that it built up when the ABV was lower? Or, is it accomplished some other way? In the case of yeast that ferment to 18% ABV, those reserves would have to be quite substantial.

This is actually a really good question. I've posted over at GotMead, I'll let ya know what Squatchy says.

 

[NeverDie]

At least with this 5 gallon batch of M05 traditional mead, the drama is over and its destiny is set. How it will finally taste and smell I do not know. SG is now 0.998, and I expect it will, after a long period of very slow continued fermentation, probably settle out at 0.995. It may well take longer going from 0.998 down to 0.995 than the fermentation that got it from 1.105 down to 0.998. That's the great frustration of the long tail.

When it gets to 0.995, I plan to transfer it to a secondary without waiting for it to clear. Good or bad idea? I think it was rph_guy who had once commented that if there had been sulfurous emissions then it's even more important to quickly get the must off of the lees.

I'm actually now kinda leaning toward maybe switching to Fresco as my go-to yeast, since it is physically incapable of making H2S. If only Fresco flocculated and cleared better, it would be an easy decision....

 

[Maylar]

Or resign to the fact that temperature control is mandatory and deal with it. Then you can use any yeast.

Yes, rack off any sulfurous lees asap.

 

[Maylar]

If it's true that the yeast can't extract nitrogen from the must above 10%, then how does the yeast meet its nitrogen needs when the ABV is above 10%? Is it drawing upon some kind of inner cellular nitrogen reserves that it built up when the ABV was lower? Or, is it accomplished some other way? In the case of yeast that ferment to 18% ABV, those reserves would have to be quite substantial.

Squatchy says:

Good question. I don't know that for sure. But I suspect that they upload as much as they need or can so they have it later down the road. I suspect they need it still, but the ABV blocks a pathway and shuts down the opportunity.

Eric the geek has more to say:

http://www.gotmead.com/forum/showth...inorganic-nutrient-timing?p=276505#post276505

 

[NeverDie]

Squatchy says:



Eric the geek has more to say:

http://www.gotmead.com/forum/showth...inorganic-nutrient-timing?p=276505#post276505

Thanks! It reads as though they recycle the nitrogen, except when it's used for building a larger population of yeast. Well, that explains a lot, especially regarding the TOSNA nitrogen additions being timed to occur no later than the first sugar break. Presumably by then the poulation will have already grown.

 

[NeverDie]

Thanks! That would explain it. When I did the successful 1 gallon M5 fermentation earlier in the year, I used one full packet (10g) of yeast. However, since then other forum members have said that 2g of yeast per gallon is more than sufficient and that even 1g of yeast per gallon is actually enough, so this time around I went with 2g/gallon.

Do you need more yeast for high gravity fermentations?
Yes, anytime you are pitching yeast into a harsh environment (high gravity, low temp) you need to add additional yeast. A rough rule of thumb is to double pitch rates above 1.065 and triple pitch rates above 1.085. Or, more technically, a million cells per mL per °Plato are needed for a 20 °Plato (1.080 specifice gravity) beer, or 3 Activator packages for a 5 gallon (19 L) batch. It is also important to remember that it is more difficult to get oxygen into the solution in a high gravity wort.​

http://wyeastlab.com/frequently-asked-questions

 

[Maylar]

Do you need more yeast for high gravity fermentations?
Yes, anytime you are pitching yeast into a harsh environment (high gravity, low temp) you need to add additional yeast. A rough rule of thumb is to double pitch rates above 1.065 and triple pitch rates above 1.085. Or, more technically, a million cells per mL per °Plato are needed for a 20 °Plato (1.080 specifice gravity) beer, or 3 Activator packages for a 5 gallon (19 L) batch. It is also important to remember that it is more difficult to get oxygen into the solution in a high gravity wort.​

http://wyeastlab.com/frequently-asked-questions

Squatchy made a thread about that at gotmead:

http://www.gotmead.com/forum/showth...rate-model-based-on-Scott-s-Lab-Handbook-2016

 

[NeverDie]

Squatchy made a thread about that at gotmead:

http://www.gotmead.com/forum/showth...rate-model-based-on-Scott-s-Lab-Handbook-2016

If Squatchy's calculations are correct, then 2 g/gallon dry yeast would cover all possibilities.

 

[NeverDie]

Thanks! It reads as though they recycle the nitrogen, except when it's used for building a larger population of yeast. Well, that explains a lot, especially regarding the TOSNA nitrogen additions being timed to occur no later than the first sugar break. Presumably by then the poulation will have already grown.

It turns out that TOSNA is apparently timed for slow fermentations. I attempted it with a small batch using M05 yeast, but at the rate it was fermenting I had to change the TOSNA protocol a tiny bit to make adding the Fermaid-O at 1.100, 1.090, 1.080, and 1.070 SG's. That was with an OG of 1.105. Currently, SG is 1.065 and all the Fermaid-O additions have been done. I'll now let it coast all the way to FG without any further nitrogen additions. In theory it should not go sulfurous and won't need any further nitrogen, and that is the theory this small test batch will be testing as it continues with its fermentation. I'll report back if it fails or after it reaches FG, whichever occurs first.

 

[NeverDie]

Perhaps TOSNA assumes a maximum pitch rate of 2g dry yeast per gallon, or thereabouts? The above batch had 3x that pitch rate, which is perhaps why it went too quickly for TOSNA. Yesterday I started a second batch with a 2g pitch rate of the same yeast (though OG is 1.108 instead of 1.105), and it's moving along much more slowly, such that the TOSNA timetable may actually fit it.

 

[Maylar]

I think gravity measurements would be better timing points anyway, since temperature also has an effect on ferment speed. As does yeast choice.
But I agree that pitch rate does make a difference. I did a 1/2 gallon cider recently and used a whole packet of S-04 and it was done in just 3 days. Yeeha.