[ScottBeh]

I searched for this lots of results, but not this exactly.

I emailed the manufacturer a couple days ago and I find that if they don't respond in 24 hours, it aint happening.

Here is the question

There is a FAQ on your site says you should not use distilled/RO for rehydration.  You recommend using GoFerm.  Is it optimal then to add GoFerm to RO/distilled to get the correct level of nutrients?  I guess my real question is what water did you use in your testing to arrive at the formula and dosage rate recommended for GoFerm?  Thank you.

Anyone have any advice on this? 

[69franx]

Follow up/ high jack... is go ferm  only for rehydration dry yeast or is it also recommended for liquid starters?

[mabrungard]

The objective is to get water molecules into the dehydrated cells. I'm not sure there is a problem with using water with very low mineralization.

[erockrph]

The objective is to get water molecules into the dehydrated cells. I'm not sure there is a problem with using water with very low mineralization.

Without any solutes to provide an osmolarity gradient, what is to keep the yeast cells from taking up so much water that they burst? You can kill someone by administering pure water intravenously; your blood cells end up taking up water to the point of lysis. Maybe someone with more experience in yeast biology has some better data, but I can certainly see a potential issue here.

[Stevie]

I had always heard this rule as well. I think Eric has the idea.

[reverseapachemaster]

You can kill someone by administering pure water intravenously; your blood cells end up taking up water to the point of lysis.

Sounds like a great murder plot.

[brewinhard]

+1 to osmotic pressure being too much for the yeast cells trying to prepare their membranes during rehydration.  Distilled water is too pure...

[hopfenundmalz]

I remember these discussions from the HBD years ago. Too much stress on the yesat, you need some minerals.

[ScottBeh]

saline solution?

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

[hopfenundmalz]

I have been using filtered tap water and a little go-ferm for years.

[ScottBeh]

Yeah.  I don't have the option. I have a whole house RO only cause I am surrounded for miles by agriculture and we have very shallow wells.  The water is pretty nasty just to get past your nose otherwise. 

[JT]

You could buy a few gallons of spring water to have on hand for starters if this is an issue.  First I'm hearing of it though, learn something every day. 

[hopfenundmalz]

You could buy a few gallons of spring water to have on hand for starters if this is an issue.  First I'm hearing of it though, learn something every day.

Ask Dan Listerman, he had the exchange with Clayton Cone about using distilled back in 2003 or so.

The HBD appears to be down.

[mabrungard]

Without any solutes to provide an osmolarity gradient, what is to keep the yeast cells from taking up so much water that they burst? You can kill someone by administering pure water intravenously; your blood cells end up taking up water to the point of lysis.

Um, osmotic pressure is very low. It should be pretty darn difficult to develop an osmotic pressure that significantly exceeds the internal pressure within the cell and causes it to burst.

The thing with administering pure water (intravenously or orally) is that it reduces the ionic content of the blood to the point that it disrupts the function of systems. It does not burst the cells or cause lysis.

[Philbrew]

You could buy a few gallons of spring water to have on hand for starters if this is an issue.  First I'm hearing of it though, learn something every day.

Or couldn't he just add some salts (Epsom, non-iodized table salt, etc.) to his RO water?  Get the TDS up around 100 ppm or so.