Hydrating Yeast...Why?

[Former Canuk]

Is there any real benefit to starting the yeast before you pitch it other than giving the brew a running start. (as opposed it pitching it in dry and giving it a good stir) I see manufactures suggest it but I’m not sure the reason why. To date I’ve only pitched dry. I’ve searched this website but cannot find the answer. Please “All knowledgeable ones” tell me why. Is it possible it can affect the outcome of the wine one way or the other?

[NorthernWiner]

The one benefit is immediately knowing whether or not the yeast is still good.

Better to find out straight away than having it float on top of your must for 2-3 days and not do anything.

[Cellar_Rat]

Good question !

IMO hydrating yeast is to reverse the effects of dehydrating it. This gets the yeast back to the point it started from before introducing it to all the other stuff in your must.

I often do a bit of both, by adding a teaspoon of sugur to the water and thus it becomes a starter.


edit ... and rehydrating does seem to make a difference!

[Former Canuk]

Thanks Gents. Not one to try and be different for no reason at all, just curious, your comments make sense and I shall join the club. Getting too old for learning the hard way!!

[koomber]

I always thought it was down to osmotic pressure.

At its simplest, osmosis means:
water moves, without input of energy, across a semipermeable membrane (permeable to the solvent, but not the solute) separating two solutions of different concentrations.

This means that if you chuck dehydrated yeast into fresh water, the yeast can very easily absorb the water and rehydrated.
The presence of sugars in the wort/must means that more of the water is tied up hydrating the sugars. The yeast will still be able to hydrate through osmosis, but will not do so as quickly and will have to expend energy sooner to rehydrate versus being in fresh water.

[Rich]

Cracking explanation there Koomber. So, even if preparing a starter to increase the yeast cell count, It'd be better to hydrate the dry yeast in plain water first before adding to the sugary solution?

[goldseal]

That's hoew I understood it too. In nonscientific terms it gives the yeast a gentler introduction, more cells will survive and fermentation should therefore be stronger / start quicker.

[Cellar_Rat]

Nice job koomber!

[lockwood1956]

Great explanation Koomber...

But as well as hydrating the yeast without osmotic shock I firmly believe that you should then make that yeast into a "starter" so that you do the lag phase in the starter bottle, meaning a much quicker start to the must fermenting, the ,must is at its most vulnerable to spoilage stage just before ferment starts, we have after all created the perfect medium for spoilage organisms.

I like to make up my starter bottle at least 24 hours before the must is ready (48hrs if I can)

regards
Bob

[koomber]

Great explanation Koomber...

But as well as hydrating the yeast without osmotic shock I firmly believe that you should then make that yeast into a "starter" so that you do the lag phase in the starter bottle, meaning a much quicker start to the must fermenting, the ,must is at its most vulnerable to spoilage stage just before ferment starts, we have after all created the perfect medium for spoilage organisms.

I like to make up my starter bottle at least 24 hours before the must is ready (48hrs if I can)

regards
Bob

Couldn't agree more. Starters are the way forward.

[Cellar_Rat]

yup

[Ted.B]

My recently purchased Vintners Harvest yeast packets state that hydration is not required, but it wouldn't do any harm if I did hydrate them would it ?

[Cellar_Rat]

My recently purchased Vintners Harvest yeast packets state that hydration is not required, but it wouldn't do any harm if I did hydrate them would it ?

Not at all. Give em a better start if anything.

[koomber]

Not at all. Give em a better start if anything.

I'm with Cellar Rat here. I'll confess to being a bit lax on the wine front of late, but I wouldn't consider using yeast without hydrating or making a starter.