Why is it advised to rehydrate dry yeast with distilled water and not with mineral-ri

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Finlandbrews

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I was just wondering what is the idea with dehydrating dry yeast with distilled water. Wouldn't it be better for yeast to have water with mineral ranges (zinc, calcium, magnesium,...) that will feed their health?

Beside water temperature and volume, what mineral compounds, pH, and other stuff in the water are important to avoid when dehydrating dry yeast?
 
I was just wondering what is the idea with dehydrating dry yeast with distilled water. Wouldn't it be better for yeast to have water with mineral ranges (zinc, calcium, magnesium,...) that will feed their health?

Beside water temperature and volume, what mineral compounds, pH, and other stuff in the water are important to avoid when dehydrating dry yeast?

I think you're talking about rehydrating dried yeast? If so, you want to make sure that the water is the right temperature and without much in it (due to osmotic pressure changes) to rehydrate the yeast.
 
Like Yooper said, I'm sure you meant to say rehydrating. Also, it's because when the yeast is dried at the manufacturer, they've already provided all of the nutrients that the cells need to build up their cell walls again after dehydration. So you want the water with nothing in it, because as the cells are being rehydrated, their won't be able to pick and choose what enters through their cell walls. Everything just rushes in. That's also why it's sometimes advised to not pitch directly into the wort. If they get inundated with all of that all at once, it can lead to osmotic shock, which at best would stress them out, and at worst will kill them off.
 
I was just wondering what is the idea with dehydrating dry yeast with distilled water.[...]

fwiw, I don't know where your reference to "distilled water" came from, but here's a direct cut'n'paste from a Fermentis spec sheet:

"Re-hydrate the dry yeast into yeast cream in a stirred vessel prior to pitching. Sprinkle the dry yeast in 10 times its own weight of sterile water or wort at 27C ± 3C (80F ± 6F)."

Nothing about "distilled".

Best as I can recall from what I've read, distilled water is pretty much a no-no when farming yeast...

Cheers!
 
IDK, I have always just used tap water. I boiled and cooled the first time. Then I just started adjusting the hot and cold taps to get the proper temperature....

But then again I read an article locally that said my town has the best water in the area and far better than some nearby towns.
 
Best as I can recall from what I've read, distilled water is pretty much a no-no when farming yeast...

I also have it in my brain that distilled for rehydrating is bad, but can't remember why. Perhaps something about lack of any mineral content.
 
fwiw, I don't know where your reference to "distilled water" came from, but here's a direct cut'n'paste from a Fermentis spec sheet:

"Re-hydrate the dry yeast into yeast cream in a stirred vessel prior to pitching. Sprinkle the dry yeast in 10 times its own weight of sterile water or wort at 27C ± 3C (80F ± 6F)."

Nothing about "distilled".

Best as I can recall from what I've read, distilled water is pretty much a no-no when farming yeast...

Cheers!


"Sterile" water is generally considered "distilled" water. It's perfect for using in rehydrating yeast.
 
I've just always used tap water boiled and cooled to about 90-100deg then drop the yeast in and go from there. After oxygenating wort with my O2 wand usually fermentation in less than 4-8 hours.
 
"Sterile" water is generally considered "distilled" water. It's perfect for using in rehydrating yeast.

No, "distilled" and "sterile" are not the same.

Boiling water does not remove the mineral content.
Distillation does exactly that.

And I'm pretty sure there's a passage in Yeast that explains why not to use distilled water with yeast...

Cheers!

[edit] Actually, you can just Google that stuff.
As well, one should not consider a gallon jug of distilled water purchased at the supermarket as "sterile".
Mineral-free, yes, but not "sterile"...
 
I always took fermentis instructions to mean "boiled". I always use filtered boiled water, cooled to rehydrate temp.
 
Don't use distilled water. Ideally you want to use sterile wort, but boiled tap water should be adequate.

[edit] Actually, you can just Google that stuff.
As well, one should not consider a gallon jug of distilled water purchased at the supermarket as "sterile".
Mineral-free, yes, but not "sterile"...

Packaged water is usually UV disinfected. It's safe to treat the unopened gallon jugs of distilled water as sterile.
 
actually, rehydrating, you want some mineral content in the water to prevent the yeast from overhydrating and bursting.
Yeast has already got some salts/minerals inside the cellwall, osmosis will equalise the water content inside and outside the cell. too much water can lead to burst cell-walls.
 
For a new brewer, it's difficult to determine which method is correct since there is always different answers.
I have used spring or filtered water to re-hydrate yeast and never had an issue.
 
I stick my thermometer under the tap, wait until the temp gets to where it needs to be, then fill my measuring cup and rehydrate.
 
I'm sure I read that distilled water is not the preferred water due to not having minerals the cells might need to complete their rehydration.

But it will work, and should work much better than rehydrating in wort, where the cells cannot regulate what come in or out yet and they can let stuff through their walls that will kill them, leading to an approximate 50% kill rate.

I've used distilled, spring water, tap water and all have worked fine. But that's anecdotal evidence. I'm guessing it was the book "Yeast" that suggested spring or tap water.

All sterile of course.
 
I'm sure I read that distilled water is not the preferred water due to not having minerals the cells might need to complete their rehydration.

But it will work, and should work much better than rehydrating in wort, where the cells cannot regulate what come in or out yet and they can let stuff through their walls that will kill them, leading to an approximate 50% kill rate.

I've used distilled, spring water, tap water and all have worked fine. But that's anecdotal evidence. I'm guessing it was the book "Yeast" that suggested spring or tap water.

All sterile of course.


Yeah I quoted the section of the book only a few posts up.
 
Yeah I quoted the section of the book only a few posts up.

May be that's where I read it, but I'm sure I had heard it mentioned somewhere else as well, before I owned that book. Might have been a TBN podcast or somewhere.

Just went back and read my last post. I meant to say I read it somewhere besides the Yeast book...
 
^ that is funny. When they had the ad campaign about "being better than Cleveland water" or something to that effect, the Cleveland folks analyzed it and found high arsenic levels.

Anyway, one would think this is simply based on osmonic pressure. Ion free water is not good for organisms, period. If you put a fathead minnow in 100% RO or Distilled water, it dies. That death is due to the osmonic pressure placed on the fry. No one would call it toxic, bit it isn't good for life.

The only thing that may be different with dehydrated yeast would be that there may be minerals/ions left behind with the yeast. So its plausible that you could use Distilled or RO water and that there would be enough material to give you a the profile that was left behind from the dehydrating process. I don't use dry yeast so I won't be experimenting but I would think a safe SOP would include using water which contained minerals.
 
^ that is funny. When they had the ad campaign about "being better than Cleveland water" or something to that effect, the Cleveland folks analyzed it and found high arsenic levels.

Anyway, one would think this is simply based on osmonic pressure. Ion free water is not good for organisms, period. If you put a fathead minnow in 100% RO or Distilled water, it dies. That death is due to the osmonic pressure placed on the fry. No one would call it toxic, bit it isn't good for life.

The only thing that may be different with dehydrated yeast would be that there may be minerals/ions left behind with the yeast. So its plausible that you could use Distilled or RO water and that there would be enough material to give you a the profile that was left behind from the dehydrating process. I don't use dry yeast so I won't be experimenting but I would think a safe SOP would include using water which contained minerals.

The way I understand it with dist or RO water the cell could absorb water too quickly and damage it.

EDIT: okay maybe not the perfect picture to explain it...

osmotic pres.jpg
 
The way I understand it with dist or RO water the cell could absorb water too quickly and damage it.

EDIT: okay maybe not the perfect picture to explain it...

Right, so I think of it as water rushing in an exploding the cells. Overly dramatic and it wouldn't look that way in a microscooe, but keeps the idea in my head. It is still a result of the osmonic pressure placed on the yeast in the environment that you are placing them in, at least as far as I can tell.

When we use to culture fathead minnows, occasionally when we would try someone new they would change the fry bucket over with RO instead of moderately hard water. This would result in almost complete death of the fry in the bucket and any that managed to survive would be tossed due to the compromise in their health.
 
Dr. Clayton Cone of Lallemand (see this link: https://koehlerbeer.wordpress.com/2008/06/07/rehydrating-dry-yeast-with-dr-clayton-cone/) states "The water should be tap water with the normal amount of hardness present. The hardness is essential for good recovery. 250 -500 ppm hardness is ideal. This means that deionized or distilled water should not be used. Ideally, the warm rehydration water should contain about 0.5 – 1.0% yeast extract."

The part about - 0.5 - 1.0% yeast extract lost me.
 
Right, so I think of it as water rushing in an exploding the cells. Overly dramatic and it wouldn't look that way in a microscooe, but keeps the idea in my head. It is still a result of the osmonic pressure placed on the yeast in the environment that you are placing them in, at least as far as I can tell.

Not overly dramatic. Here is a video i took today of a yeast culture resuspended into distilled water

test.gif
 
You should just use tap water. Danstar's official response to a question about distilled water:

http://www.danstaryeast.com/articles/dry-yeast-rehydration-conditions

You want the water sterile, so you boil it, but you do not want it to be distilled. Distilled water is water with no minerals in it, sterile water is sterilized water. Distilled water will actually cause yeast cells to burst and die because it will suck minerals out of the cells via reverse osmosis (side note: this is the same reason you do not want to drink distilled water). Boil tap water, cool it down to 105 F or lower and then add the dry yeast.
 
Not overly dramatic. Here is a video i took today of a yeast culture resuspended into distilled water

That's really cool.

Is this what we are seeing?

  • Single yeast cell
  • Exposed to distlled water
  • Cell lysis and the cytoplasm being extruded ito the media.

All the instructions I've ever read from the manufacturers specify sterile water or wort and some clearly advise against use of distilled water for the reasons this video illustrates.
Danstar's response to this question.
 
You should just use tap water. Danstar's official response to a question about distilled water:

http://www.danstaryeast.com/articles/dry-yeast-rehydration-conditions

You want the water sterile, so you boil it, but you do not want it to be distilled. Distilled water is water with no minerals in it, sterile water is sterilized water. Distilled water will actually cause yeast cells to burst and die because it will suck minerals out of the cells via reverse osmosis (side note: this is the same reason you do not want to drink distilled water). Boil tap water, cool it down to 105 F or lower and then add the dry yeast.

Thanks for the reply talgrath! Now if we consider that the water is sterile by boiling it, would that tap water be better than bottled water? If we treat water for mashing, couldn't we treat it too for rehydrating dry yeast? Why I ask these is because :

1) yeast needs oxygen and boiling removes oxygen from the water

2) boiling doesn't remove chloramines and other amines compounds, are they affecting yeast

3) what if some mineral ranges dramatically change during boiling too

4) what about the best pH for yeast as tap water is usually above pH 8
 
You should just use tap water. Danstar's official response to a question about distilled water:

http://www.danstaryeast.com/articles/dry-yeast-rehydration-conditions

You want the water sterile, so you boil it, but you do not want it to be distilled. Distilled water is water with no minerals in it, sterile water is sterilized water. Distilled water will actually cause yeast cells to burst and die because it will suck minerals out of the cells via reverse osmosis (side note: this is the same reason you do not want to drink distilled water). Boil tap water, cool it down to 105 F or lower and then add the dry yeast.

Thanks for the reply talgrath! Now if we consider that the water is sterile by boiling it, would that tap water be better than bottled water? If we treat water for mashing, couldn't we treat it too for rehydrating dry yeast? Why I ask these is because :

1) yeast needs oxygen and boiling removes oxygen from the water

2) boiling doesn't remove chloramines and other amines compounds, are they affecting yeast

3) what if some mineral ranges dramatically change during boiling too

4) what about the best pH for yeast as tap water is usually above pH 8
 
Would it be better than bottled water? I'm not entirely sure, but it does work just fine.

1. The oxygen should be present in the wort if you are properly oxygenating your wort (and you are, right?), remember we're not fermenting the water.

2. I haven't noticed any negative effects.

3. I'd say they probably do...but again I haven't noticed any differenes.

4. What tap water are you drinking? Mine sits around 7.4.

Overall, remember that when we soak the yeast there's no fermentation activity, we're just rehydrating it before adding it to the wort. 15 minutes, even in a slightly less than ideal condition, is probably just fine as long as it isn't outright killing yeast (like distilled water would do).
 
I imagine you can boil & cool most any non-distilled or RO water & it will be fine. I have used water from the tap, filtered water from my fridge, & the spring water I brew with, and never had any problems. My tap water tastes & smells like a swimming pool, but boiling it drives off chlorine/chloramines, so no worries there. (Note - this is why I use Kroger-brand spring water.)
 
I remember how my mother when baking fresh bread would take the dry yeast add it to warm water with a teaspoon of sugar just to see if the yeast was good, I'm pretty sure this is how re-hydration got started, as I remember it was just tap water or even well water and in all cases it worked, you just let it set until you see a small layer of foam on top....I think people are getting carried away with the details too much...as Nike said years ago which i just love this saying ...."just do it"
 
I imagine you can boil & cool most any non-distilled or RO water & it will be fine. I have used water from the tap, filtered water from my fridge, & the spring water I brew with, and never had any problems. My tap water tastes & smells like a swimming pool, but boiling it drives off chlorine/chloramines, so no worries there. (Note - this is why I use Kroger-brand spring water.)


Try a batch of your tap water treated with campden. You most likely won't regret it, and save $$ per batch along the way.
 
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