Re-Hydrate v Not..

[Dengue]

And Danstar state a different method for its yeast

Oh yes

Pitching Rate: 1g/L


Step 1.

• Sprinkle the yeast on the surface of ten (10) times its weight of clean, sterilized (boiled) tap water at 30 - 35°C (86° - 95°F)
• DO NOT STIR !!!
• Leave undisturbed for 15 minutes at 30 - 35°C (86° - 95°F)
• Foam or no foam is not an indication of vitality

Step 2.

• After 15 minutes stir until all yeast is suspended
• Leave undisturbed for another 5 minutes.
• Adjust temperature of solution to that of the wort in 10°C (18°F) steps, by adding small amounts
  of wort at 5 minutes intervals and mixing gently (ATTEMPERATION)

Step 3.

• After attemperation inoculate without delay.
• Aeration of wort is not necessary.

But why tap water and not distilled water is interesting...

Interested in giving dry yeast a try and have a rehydration question. From the instructions on Danstar's website, it states that distilled or reverse-osmosis water should not be used. For those of us with water unsuitable for brewing, any suggestions for a rehydration water recipe (salts, yeast nutrients) starting with RO water? Thanks in advance.

Joe Gibbens


RESPONSE:
Joe,

We do not recommend to use distilled or reverse-osmosis water because the yeast would be damaged by osmotic pressure. Tap water contains minerals which lower the osmotic pressure on the yeast. You could rehydrate the yeast in a 0.9 % saline solution.

We have a nutrient specifically developed for rehydration of dry yeast called GoFerm. This nutrient is widely used in the wine industry and supplies the yeast with sterols and minerals during rehydration process.

Regards,
Forbes & Tobias

But definitely no glucose, hmm.

 

[Bizier]

That would be a rocking horse?

This thread does not rock

 

[Pickaxe]

It needs a medicinal bullet to the brain.

 

[bradsbrew]

I must say that if a new brewer cannot decide if rehydrating is or isnt for them after reading this thread, perhaps another hobby would suit them. There is some good info
inbetween all the dribble and crap within this thread.

But that is just my 35.6F worth.

 

[bum]

I'd be advising any new brewer (or old brewer) to stay the hell away from this thread if they were looking for information (regardless of the quality of any single post).

My 275.15 kelvin.

 

[Yob]

Somewhere in between sterile water and sterile wort is sterile glucose.

Glocose is never a great idea to proof / grow yeast, Yeast will produce a certain set of enzymes to deal with the sugars available, if it then differs from the sugars you put them into (Your Wort), they need to stop and make a new set, this increases lag time and or respiratory issues can then occur. This is why, if you can, you make a starter from the same wort you are going to pitch to.

This is the great Botchalism thread of 2013.

:unsure:

 

[Lecterfan]

But why tap water and not distilled water is interesting...

I don't think it's mean to be taken literally as 'cheesemakers' so much as referring to manufacturers of all dairy products...

I am sure distilled water would be fine...but most of us have access to a tap and a kettle.


edit: disregard, I'm wrong - see below.

 

[Parks]

I don't think it's mean to be taken literally as 'cheesemakers' so much as referring to manufacturers of all dairy products...

I am sure distilled water would be fine...but most of us have access to a tap and a kettle.

I'm pretty sure some mineral content from tap water is beneficial in rehydration.

 

[Ducatiboy stu]

More like a mule....

I raise you an ass

 

[Lecterfan]

Cool, I haven't read that before, wouldn't surprise me - but 'tap water' could be anything really. My limited understanding is it was about making the cell walls nice and comfy before the beasts go to work and that in terms of minerals etc the dried yeast has all that it needs stored up in the drying process. Still, I have nothing to back me up and really was just keen to contibute to this thread so I have some legacy haha!

...aaaaaand edit: nope, I'm wrong! Apparently distilled water is not friendly at all...once again my big mouth and I beat a hasty retreat haha

 

[Ducatiboy stu]

I must say that if a new brewer cannot decide if rehydrating is or isnt for them after reading this thread, perhaps another hobby would suit them. There is some good dribble and crap inbetween the info within this thread.

But that is just my 35.6F worth.

 

[GalBrew]

I raise you an ass

Touche........

 

[Dengue]

Thanks for that contribution, Stu.

The question now becomes, does osmotic pressure of pure water kill more yeasts than wort on contact ?

 

[Yob]

Does it matter? Anything that's killing them is surely bad practice...

 

[Dengue]

Does it matter? Anything that's killing them is surely bad practice...

Indeed, but we need the lesser of both evils.

slash tells me that wort kills 50% on contact if I pitch dry yet danstar tells me if I use pure water to hydrate I will pop them like a balloon but they don't say how many.

 

[Yob]

Most of them would be my assumption.. Either way, it's bad practice. Bad practice should be eliminated as much as possible from the brewery..

 

[mmmyummybeer]

Could edge your bets and rehydrate in a watered down wort mix :unsure:

 

[Dengue]

Could edge your bets and rehydrate in a watered down wort mix :unsure:

seems what this is leading to


In summary:

wort is poisonous if absorbed through the cell wall prior to biomechanical machinery kicking in
pure water will cause the cells to pop like an over inflated balloon

so yes maybe somewhere in between is the answer.

I'd like to see a controlled experiment on this.

In the meantime, seems I better use liquid yeast till I figure this out. :huh:

 

[Ducatiboy stu]

17 pages and still we dont have an answer that suits everyone...

Did you know distillers use tomatoe paste for there yeast......

 

[Yob]

The answer has been stated many times just some don't accept it.