Rehydrating Your Yeast

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I've also got a friend who's convinced that adding a campden tab to water will dissipate the chlorine and chloramine as well but I have done no research on it and can't tell you what chemical reaction that would be...

Your friend is correct.

See Here for some scientific data - you'll note that ascorbic acid (Vit C) can also be used to remove chlorine, but may not remove chloramines.

This page describes the reactions and I've cut and pasted the tables below.

Although I don't recall the exact dosing, I believe 1 Campden tablet will treat about 40 gallons of water.
 
Your friend is correct.

Although I don't recall the exact dosing, I believe 1 Campden tablet will treat about 40 gallons of water.

Thanks, Medsen. Your search-fu is stronger than mine, when he first mentioned it I did a cursory search and didn't come up with anything useful.

I think he was using 1 tab for a 5-gal cooler but likely only because cutting them in half is a pain and a little extra won't hurt anything, the amount of dissolved CL2 is quite small so that dosing makes sense... Thanks for explaining the mechanism, it makes a little bit of hydrocholoric acid out of the chlorine. He just told me it converted into yeast food, which sounded hokey to me.

I know our water uses chloramines so I did a bit more poking around and came up with the equation for chloramine, it's just using another step of dissociation of the chloramine in water to get to hydrochloric acid and sodium sulphate, plus the leftover ammonia.

NH2Cl + H2O <-> NH3 + HOCL
NaHSO3 + HOCL <->NaHSO4 + HCL

I guess it still leaves you with a tiny bit of ammonia in solution, which is a problem for an aquarium but likely what he was calling yeast food, since I think they can use that. Not so hokey after all :)
 
Yeah, it's simple science, the yeast are dehydrated so you need to rehydrate them with water BEFORE you feed them sugar, otherwise there is an osmotic effect which will tend to pull the water OUT of the yeast at higher sugar concentrations (like drinking straight honey to rehydrate yourself - yeah, there's some water in there but drinking it when you're dehydrated is the opposite of help, whereas the goferm would be like adding some Gatorade powder to your water to help rehydrate you). When I make a starter for a high-gravity must, I give my yeasties 15 min in their 1/4 cup of water, then I add 1/4 cup of must and double it every time I see a little activity (20 min-2 hours depending on the situation) till I have a nice amount of happily frothing must. I've just never had it foam up like crazy even after leaving it overnight.

Hmm, That is interesting. Now from what I have experienced is that it hasn't hurt the yeast. Also, the website posted later says:

"Thirdly, a starter properly made, using water, a small quantity of the must itself or a juice substitute (grape, orange or apple juice) and some nutrients, will acclimate the yeast to its destined environment. When the starter is added to the primary, it will practically explode with activity and do what nature and selection programmed it to do and do it that much more efficiently."

Which is essentially what I am doing, Using mostly water at room temp, the heated Must that I add is usually only about a tablespoons worth for a cup volume. The Must also has my DAP or Yeast Energizer and Yeast Nutrient mixed in at that point. So by te sounds of the website post, I am doing it right. With the exception of the temp. I would have to guess that the resulting temp is about 80F. Ofcourse this is also in Colorado so I don't know that Altitude has any effect. Logically, for oxygen density and boiling temp differing at 5000 ft above sea level should have some effect.

With my method, I always end up with a very dense starter that has foamed up a lot and then calmed down a bit. Never had a dud yeast pack.

So, I don't know. By the sounds of things the initial yeast has time enough to replicate past the crumpled stage and have some starving but very eager and active yeastie beasties.

I am in process of improving my brews though, much thought. I don't do step nutrients, just put it all in at once and let it go, rack at about a month when it slows down. and rack again when clearing with sparkloid if neccessary. I usually do about 3-4 rackings total before I am done, ofcourse I put in the element of oaking, fruit, spices, all on seperate rackings to layer in the flavors. so I don't know.

matrix
 
The Must also has my DAP or Yeast Energizer and Yeast Nutrient mixed in at that point.

Current wisdom suggests that DAP not be included in any rehydration because it can 'burn" the yeasties, many don't even add it until after the lag phase. Although if it's diluted in your must and you don't use much must in your starter it's probably fine. That said, for the last six years I added my DAP to the must right before I dry-pitched the yeast and it doesn't look like it's ever hurt anything.

But again, you never know what final effects may result from early yeast abuse...
 
With Lallemand yeast, it is definitely recommended not to use DAP during the rehydration. During rehydration, the membranes of the yeast are "leaky" and they cannot properly regulate the uptake of ammonium ions. This can lead to toxicity. While the effect of mixing in some must with DAP included will probably be negligible from what you can see with the eye, it may cause lower viable cell counts.

Proper rehydration is important, especially the temp. Below about 90F, the phospholipids of the membrane may crystallize causing damage to the membranes as Oskaar has described. However, there are some companies, like Vintner's Harvest which recommend dry pitching of their yeast. They claim to have data showing this results in the highest cell counts. I have asked them to show me such data, but have received nothing to date. What I can say is that from the published scientific studies on rehydration of ADY, the process folks here are describing has been shown to produce the greatest number of viable cells.
 
The way that I look at is this: I'm sure that good, even great, mead can be made with any method, rehydration perfectly, imperfectly, no rehydration at all. But, the science (and experience of many senior mead makers) says that the exact same recipe that makes a good/great mead with dry pitching yeast, would make an even better mead with proper rehydration. I don't find it difficult, expensive, or overly time consuming to rehydrate as best as I can, so that's what I do. Frankly, I find that part of the process one of the more fun parts. :)
 
But, the science (and experience of many senior mead makers) says that the exact same recipe that makes a good/great mead with dry pitching yeast, would make an even better mead with proper rehydration.

That might be stretching it just a bit.
However, properly rehydrated yeast, especially those pampered with appropriate rehydration nutrition like GoFerm (or similar products) that supplies sterols, minerals and amino acids for nitrogen, will be able to achieve greater biomass, will have greater alcohol tolerance, will have a higher chance for complete fermentation, and will have a lower risk of sulfur odors.

If you are not rehydrating and getting great results, that's certainly OK, but if you try a lot of different recipes (especially some of the extreme brews we aim for) you'll run into situations where the proper rehydration will make a difference. I prefer to try to optimize the yeast I pitch in every case.
 
That might be stretching it just a bit.
However, properly rehydrated yeast, especially those pampered with appropriate rehydration nutrition like GoFerm (or similar products) that supplies sterols, minerals and amino acids for nitrogen, will be able to achieve greater biomass, will have greater alcohol tolerance, will have a higher chance for complete fermentation, and will have a lower risk of sulfur odors.

If you are not rehydrating and getting great results, that's certainly OK, but if you try a lot of different recipes (especially some of the extreme brews we aim for) you'll run into situations where the proper rehydration will make a difference. I prefer to try to optimize the yeast I pitch in every case.

To clarify: you're saying if you're producing a good mead by dry-pitching, rehydrating isn't gonna make much of a difference, but rehydrating will mitigate some potential issues (fusels, sulfur, stuck ferments) if other conditions (temp, OG, O2 content) aren't ideal?
 
That might be stretching it just a bit.
However, properly rehydrated yeast, especially those pampered with appropriate rehydration nutrition like GoFerm (or similar products) that supplies sterols, minerals and amino acids for nitrogen, will be able to achieve greater biomass, will have greater alcohol tolerance, will have a higher chance for complete fermentation, and will have a lower risk of sulfur odors.

If you are not rehydrating and getting great results, that's certainly OK, but if you try a lot of different recipes (especially some of the extreme brews we aim for) you'll run into situations where the proper rehydration will make a difference. I prefer to try to optimize the yeast I pitch in every case.

I'm under the impression that less stressed out yeast will simply produce less off flavours and aromas as well (above and beyond obvious flaws like sulphur), so the final product could potentially be cleaner tasting/smelling, and maybe need a little less aging. But, until I do some side by side testing some day I won't really have something in front of me to compare.
 
To clarify: you're saying if you're producing a good mead by dry-pitching, rehydrating isn't gonna make much of a difference, but rehydrating will mitigate some potential issues (fusels, sulfur, stuck ferments) if other conditions (temp, OG, O2 content) aren't ideal?

To me it's pretty simple. If you don't want to change the way you're making mead, and you're happy with what you have, don't change it.

If you're curious, try something different and check the difference with friends via a blind tasting.

I will say that over the years I have tasted literally hundreds of meads that people viewed as good mead and very, very few of them were actually good. The methods varied but both dry pitching and "pitch and pray" were pretty common to the processes cited. I'd actually go so far as to say that none were great, and I told them so in polite, but no uncertain terms because they asked for an honest evaluation. IMO dry pitching will yield passable mead. I've done it and had passable mead, sometimes I would get a good mead.

If you want consistent high quality mead that ferments clean, matures smoothly, and continues to age and improve, strong, fast, clean and healthy fermentations are key. If you want consistent quality fermentations, you need to rehydrate your yeast. I'm speaking specifically of Lallemand and Lalvin yeast when I say this. There are other manufacturers that recommend other things. Their processes are probably different than Lallemand's, and they probably have a different end product as a result.

Bottom line, use the method recommended by the yeast manufacturer for inoculating your must with their product.

Cheers,

Oskaar
 
Thank you everyone for contributing to this discussion,good stuff to think about all around. This compilation of "why should I change if what I'm doing works" versus "why shouldn't I do the best that I can for my yeast every time" is definitely worth a couple of test batches, especially in light of what Oskaar was saying about good vs great, but I guess it also depends on your palate as well... I think my "taste of abuse" test series will be six 1-gal batches, aiming for 11% and 16% to note the difference between a high-grav and lower-grav pitch, each with pitch and pray, simple rehydration and if I can get my hands on go-ferm I'll try that as well, if not, I'll vary rehydration water temperature.
 
After following all this discussion on rehydrating, I'm wondering if anyone here has ever done a JAO side-by-side comparison of JAO as Joe directs vs JAO with <*gasp*> rehydrated Fleischmann's?
 
On the to-do list... but my brew store doesn't carry go-ferm, I'll check out the other place in case they have it...
 
On the to-do list... but my brew store doesn't carry go-ferm, I'll check out the other place in case they have it...

I haven't found one yet that does either, I just bite the bullet and order from morewinemaking.com whenever I need more supplies that are "exotic" like new yeasts, nutrients, enzymes, etc. Paying for shipping sucks, but I generally only have to do about 1 order at around 80-100 bucks worth of stuff every year, or year and a half, depending on how much I make.
 
I haven't found one yet that does either, I just bite the bullet and order from morewinemaking.com whenever I need more supplies that are "exotic" like new yeasts, nutrients, enzymes, etc. Paying for shipping sucks, but I generally only have to do about 1 order at around 80-100 bucks worth of stuff every year, or year and a half, depending on how much I make.

I had to order mine from midwest supplies, it's way cheaper to buy in bulk (at least 80g)

As for the results of rehydrating & giving it nutrients, I don't recall anyone reporting their results to this in particular, but it's generally assumed the wine would have a much higher ABV and be much Drier possibly requiring backsweetening.
 
As for the results of rehydrating & giving it nutrients, I don't recall anyone reporting their results to this in particular, but it's generally assumed the wine would have a much higher ABV and be much Drier possibly requiring backsweetening.

This is true if one is making mead in the method of starting with a higher gravity and hoping the yeast stop where they're supposed to - but even then, at least it would be more consistant, with the dry pitch method as I understand it yes it's likely to ferment less, but unpredictably so most of the time.

But, for those who ferment dry and then stabilize and backsweeten, this changes nothing other than giving you a cleaner ferment.

And for those like myself who are fermenting to bone dry anyways, it's all good!
 
This is true if one is making mead in the method of starting with a higher gravity and hoping the yeast stop where they're supposed to - but even then, at least it would be more consistant, with the dry pitch method as I understand it yes it's likely to ferment less, but unpredictably so most of the time.

But, for those who ferment dry and then stabilize and backsweeten, this changes nothing other than giving you a cleaner ferment.

And for those like myself who are fermenting to bone dry anyways, it's all good!


True, but my answer was mostly in response to TheAlchemist's question regarding JAO which has a very high SG and is meant to finish sweet.

In this context my answer might make more sense :)