Staggered Nutrient Questions (why?)

[AK_Dreams]

I am confused regarding staggered nutrient additions. My first two meads done last August totally pooped out before reaching their peak alcohol content. Well, one of them never actually started, and the other just never got close to a fever pitch. So we repitched them both with more nutrients and EC-1118. Anyway, those are done and bottled now. We learned a little bit more about mead nutrients, ordered the right stuff online because the LBS mostly caters to beer makers and now we throw all the nutrients into the must right before we pitch the yeast and aerate with a drill mixer heavily before and after pitching the yeast. Then we let it sit and don't touch it again until it is done with primary fermentation. We are getting primary fermentation to complete in about 7 days. It hits fever pitch within 36 hours and stays that way for a few days, then we rack it into a carboy when it's bubbling every 10(ish) seconds. We rack again after about two weeks when it had dropped most of its sediment, then we let it sit until we are ready to determine whether we want to add additional, flavors, honey, or oak.

So I guess I don't understand what the staggered nutrient additions are for? I mean, why go to the trouble to stir in different nutrients every few days (or hours) if you are fermenting happily along? Why wait for a lag in the fermentation if you can give it enough nutrients to not have a lag? Or is there something I am missing? It is only necessary for high gravity musts? Or is there a reason to not have a fast ferment and to prolong the ferment by only giving the yeast nutrients every few days?

Thanks!

Sarai

 

[mmclean]

If you would use the search tool, you would find more information than you ever dreamed.

More information than any one person could or would sit and write in one sitting.

The search tool really is your friend.

 

[Chevette Girl]

The search tool really is your friend.

... and even when you scream at it in frustration, it's still your friend... "staggered nutrient addition" or "SNA" should get you some hits.

I only stagger the nutrients if I am working with a high-gravity must or a traditional mead (no fruit) in the hopes that being nice to my yeasties will make everything better. I've only started using yeast energizer in the last year, and prior to that I always tossed the nutrients in just before pitching too, I don't think it's ever caused me a problem, but then I'm generally the opposite of control freak when it comes to wines, I just let the yeast fight its own fight and try to be happy with the results.

And my "lazy staggering" method is to take the total of the nutrients and energizer that I'd be using for the whole batch, put it in a small sanitized container, then add a bit of it every time I go in to aerate... if it's been a while since last aeration, I give it a little more, if I'm faithfully aerating it three times a day, a little less.

 

[AToE]

I always stagger my nutrient additions, because it's better for the yeast (would you rather get all your nutrients once per week or in meals? ) and because I'm aerating anyways so it's no extra trouble at all (yeast need O2 for the first 1/3 - 1/2 of fermentation).

Definitely do some searching, there are very good, but complex answers to your questions out there.

I'll start with one answer though - why wait until after lag? The same reason we never use any nutrients that contain DAP during rehydration (using a DAP-less nutrient such as goferm which is specifically intended for rehydration is a great idea though). DAP hurts yeast before they're done rehydrating and fully back to life, waiting until lag is over ensures that the yeast are definitely awake and kicking before getting some DAP to feed on (note, most nutrient blends do contain some DAP).

If you want even more info than that, it is around on this site, there are discussions that go as in depth as to explain why DAP damages the yeast during rehydration (has to do with their cell walls not being up and running properly if I recall correctly).

We stagger the nutrients because it's all about not stressing out the yeast - it's not just to reach peak ABV production, it's to produce a better tasting/smelling mead. It is totally possible to create great meads without SNA though (some apparently can even do it without nutrients entirely), it's just a choice we make.

 

[Chevette Girl]

I'll start with one answer though - why wait until after lag?

I know nutrient is not a good idea while yeast is rehydrating, but I thought some of the nutrients we add were supposed to be for making healthy cell walls etc in new yeasties, how does it do any good to wait until after lag where the yeast have already done the majority of their replicating? Or am I wrong about what the nutrients are for?

 

[wayneb]

The yeast actually haven't necessarily done the majority of their replicating by end of lag. In fact, since more ethanol is produced by yeasts actively replicating as they ferment, encouraging continued reproduction through as much of what is traditionally referred to as the "anaerobic phase" as possible is a good idea. When you stagger additions of your nutrients, especially yeast assimilable nitrogen (YAN) compounds, through the first third to half of the primary fermentation interval, you help to encourage your yeasties to be fruitful and multiply throughout that period. ;D

Doses of YAN before yeast have completely rehydrated are generally toxic to the yeast, as was discussed in some detail in earlier threads on the forum. But doses of YAN before lag is over (i.e. before the yeast colony has built up cell density numbers sufficient to show macroscopic signs of fermentation - CO2 bubbles), can actually nourish spoilage organisms as well as your yeast, and in the worst case those spoilage organisms can take hold before your yeast have a chance to. An excessively large YAN dose right up front can encourage yeast to reproduce too quickly, which can lead to temporary build up of the colony to cell counts that aren't sustainable, and then the colony crashes - sometimes sticking your ferment in the process.

So, by most of our experience, several smaller additions of nutrient, starting just after lag is over and finishing up around the 1/2 sugar break point, seem to give the colony just what it needs, just when it needs it. That's the fairly simple rationale behind SNA and why it seems to work.

 

[AToE]

It should be mentioned that we say wait until after lag to add nutrients containing DAP, not nutrients in general. Your question pretty much has just one simple answer: goferm. ;D

 

[Tiwas]

Sorry to hijack this, but...what's "lag" when it comes to fermentation? I know what the word means, just not when it comes to brewing

 

[mmclean]

Sorry to hijack this, but...what's "lag" when it comes to fermentation? I know what the word means, just not when it comes to brewing

Lag is the time period from when you first pitch your yeast, until you can see signs of active fermentation (bubbles, foam on top of your must).

 

[Tiwas]

Lag is the time period from when you first pitch your yeast, until you can see signs of active fermentation (bubbles, foam on top of your must).

Cool! Thanks i pitched the yeast before I went to bed. The next day it was happily burping

 

[wayneb]

It should be mentioned that we say wait until after lag to add nutrients containing DAP, not nutrients in general. Your question pretty much has just one simple answer: goferm. ;D

More specifically, use GoFerm as a rehydration nutrient for your yeast. I wouldn't recommend adding any more to the must after pitching and before lag is over, because it, too, can become a nutrient source for spoilage organisms. The trick is to give your yeast a leg up on the competition by rehydrating with something like GoFerm, then let them clearly dominate the fermentation before you add any additional nutrient of any kind.

 

[AK_Dreams]

Wow! I have learned so much in this thread. It feels like every time I think I get the hang of something mead related I learn something new and there is a whole new world opened up.

I have been rehydrating yeast with go-ferm but I didn't know that DAP was bad for the early life of yeast. I'll do some research on sugar breaks before I ask a question about that here.

Thanks for the replies everyone!

Sarai

 

[Medsen Fey]

Another advantage of staggered nutrients is decreased sulfur odor production. When yeast get a big load of nutrients at the beginning, they can be gluttons gobbling it up quickly and later in the fermentation, when the nitrogen is depleted, they can suddenly feel nitrogen starved and get stinky. They behave somewhat like a child that you give lots of sugar sweets to - they go gangbusters for a little while then get really cranky.