Rehydrating Your Yeast

[Fred Bee]

Greetings all...this is my first post here on the forum. Just recently started making one gallon batches of mead. My last batch was a pear melomel. Now to my question...

I was told that when you rehydrate your yeast (prior to pitching) that you should open the pack of yeast (Lalvin D47) and add to a small bowl of warm water about 94 degrees and let it set for 15 minutes prior to pitching. This is what I have done. However, I was also told the yeast would start getting active and bubbly prior to pitching. In my case, I have not noticed much action with the yeast getting bubbly in the small bowl prior to pitching.

That said, after pitching my yeast into the mead, within the next 24 hours every batch seems to be chugging along nicely. So, the yeast is obviously actively working and doing its thing. All this said, I suppose my question is, do I need to do anything differently to rehydrate my yeast? Or...is it as simple as adding it to the warm water - waiting 15 minutes and pitching it in? Thanks in advance for your help and advice.

 

[wildoates]

Yep, most of us add Gro-Ferm to the water when hydrating the yeast. Works a treat as far as I can tell.

 

[wildoates]

Oh, and welcome to Gotmead!!!!

 

[YogiBearMead726]

Also, try having the warm water at 104F next time, not 94F. Something else that some people like to do (not necessary, but is an easy additional step) is to add some of the must you want to ferment into the rehydration vessel. That should give you active bubbling before pitch.

Otherwise, just rehydrate in some warm water, wait 15 min, then pitch.

And welcome to GotMead! ;D

 

[Chevette Girl]

Heathen that I am, I usually just dry-pitch (sprinkle directly from the packet on top of the must) unless it's a high-gravity must (more than 3.5 lb of honey in a gallon of water or SG above 1.120). And when I rehydrate with water, I don't usually see/smell activity with wine yeast the way I do with bread yeast.

Welcome, and how did your pear mel turn out? Others on this forum seem to think pear's a very subtle flavour but I ferment something with pears every year and mine always seem to come out pretty dominantly pear flavoured.

 

[AToE]

Something else that some people like to do (not necessary, but is an easy additional step) is to add some of the must you want to ferment into the rehydration vessel. That should give you active bubbling before pitch.

Just for clarification, this must is added after 15 minutes of rehydrating in just water, or water and goferm, then you let it sit for a while (10 minutes, whatever) and pitch that. This gets your yeast ready for the temperature and sugar content of the must.

I personally often do this in two steps, 15 minute rehydration, add about a cup of must, wait 10 minutes, add another cup, 10 minutes, then pitch. Sometimes even more steps.

I never really see the yeast apear to be active when rehydrating them until I add the must.

 

[YogiBearMead726]

Just for clarification, this must is added after 15 minutes of rehydrating in just water, or water and goferm, then you let it sit for a while (10 minutes, whatever) and pitch that. This gets your yeast ready for the temperature and sugar content of the must.

I personally often do this in two steps, 15 minute rehydration, add about a cup of must, wait 10 minutes, add another cup, 10 minutes, then pitch. Sometimes even more steps.

I never really see the yeast apear to be active when rehydrating them until I add the must.

Ah, yes. Thanks for clarifying the time schedule for that.

 

[Fred Bee]

Thanks all for your helpful comments. I appreciate learning more about this and how others prepare their yeast prior to pitching. Chevette Girl...in response to your question about my pear melomel, it is not far enough along to be ready for tasting just yet...but when I do, perhaps I can report on how it came out.

 

[mccann51]

Just for clarification, this must is added after 15 minutes of rehydrating in just water, or water and goferm, then you let it sit for a while (10 minutes, whatever) and pitch that. This gets your yeast ready for the temperature and sugar content of the must.

I personally often do this in two steps, 15 minute rehydration, add about a cup of must, wait 10 minutes, add another cup, 10 minutes, then pitch. Sometimes even more steps.

Have you noticed a reduction in lag time?

 

[Oskaar]

Okay folks, let's not forget to mention that you need to stir the yeast until there are no clumps whatsoever left in your yeast slurry.

Rehydrating your yeast works better when you have the yeast in a clean and sanitized mixing vessel and you add the 104F water to it rather than adding the dry yeast to standing water. Just think of hot cocoa, instant soup or bouillon. It blends and dissolves easier that way.

You want to stir the be-jeezus out of it until there are no clumps, and no undissolved yeast in your mixing vessel. Then let it sit for 15 minutes and stir again, then let it sit for 5 minutes. Once the 5 minutes are up, add an amount of your must equal to twice (2X) the amount of your yeast slurry.

So if you have a 200 ml yeast slurry, you add 400 ml of the must, then stir and allow to stand for 5 more minutes. If there is a temperature difference between your must and your yeast slurry of 18F or greater you will need to do an atemperation step for each 18F degree difference until the must and the slurry are less than 18F apart in temperature.

If you follow the instructions and are careful about checking your temperatures and making sure your yeast is fully dissolved before letting it rest between steps, your fermentation will take off like a rocket.

Cheers,

Oskaar

 

[AToE]

Nice, thanks Oskaar, that's good refinement on my current process, I'll follow that from here out.

mccann51 - no, I haven't noticed a specific decrease in lag time. My lags are generally all over the place, usually between 1-4 hours, sometimes as much as 12 in a mead. I haven't been acclimatizing the rehydrated yeast for long enough/enough batches yet to really be able to say for sure it's decreasing lag.

It's one of those things though, even if my observations don't tell me it's helping, scientifically I know it is so I'll do it - also, I don't generally expect big changes in my product from any one new step or process, each one is just another brick in the wall, when I add 15 new techniques all together I can definitely see my meads improve (generally I see the improvement in how early it's drinkable, and how truely "clean" it is once it's aged).

 

[Oskaar]

Happy to help.

Also, just a quick note. When I make wine I have yet to wait the entire 5 minutes after I add the must to the slurry. The reason is the yeast is already taking off and the resultant bubbling and CO2 production will boil over the top of the vessel.

I pitch that foaming, rabid, frothy, growing slurry into the the must and it is like watching a kettle start to boil!

Cheers,

Oskaar

 

[Chevette Girl]

When I make wine I have yet to wait the entire 5 minutes after I add the must to the slurry. The reason is the yeast is already taking off and the resultant bubbling and CO2 production will boil over the top of the vessel.

More evidence that yeast love grapes but have a harder time with honey? ;D

Your yeast are far more vigorous than mine, mine generally get the job done in good time but I don't think I've ever had a wine yeast get that excited about any must, maybe there's something to this 'goferm' stuff

 

[Loadnabox]

Oskaar,

I'll definitely give this a try next time.

I'm very curious about the deviation. Directions on a pack of Lallevin yeast say NOT to stir until the 15 minutes are up, then stir it all into suspension.

Any word on why it is better to pre-stir it up?

 

[Chevette Girl]

In my experience, if you sprinkle it on top of your rehydration water, the Lalvin yeast just spreads out on the top and doesn't clump unless you stir it, which is probably why they recommend against.

 

[Matrix4b]

The way that I do my yeast is:

I pull out a plastic cup, put 1/4 room temp water and put 1/4 of my hot must, or rather warm must. Then I put in my yeast and stir with a sanitized spoon. I then go back to my must and wait about 1 hr for my must to be cool enough to toss the yeast.

What happens in that time is that the yeast bubbles up and I get about 1/2 a cup of foam. I then toss that in my Must when it is of proper temp to toss the yeast.

The reason why you get no activity is that the yeast have no sugar to eat. Try puting a teaspoon of sugar and disove it in prior to putting the dry yeast in the bowl. The yeast might be a little starved for nutrients until you put it in the must but it should become active and come back to life.

The reason I use a plastic cup is so that I can toss the cup and so I don't need to sanitize it. Oh, an I put the cups in an empty sink in case of overflow. It has happened once or twice.

Matrix

 

[Loadnabox]

The way that I do my yeast is:

I pull out a plastic cup, put 1/4 room temp water and put 1/4 of my hot must, or rather warm must. Then I put in my yeast and stir with a sanitized spoon. I then go back to my must and wait about 1 hr for my must to be cool enough to toss the yeast.

What happens in that time is that the yeast bubbles up and I get about 1/2 a cup of foam. I then toss that in my Must when it is of proper temp to toss the yeast.

The reason why you get no activity is that the yeast have no sugar to eat. Try puting a teaspoon of sugar and disove it in prior to putting the dry yeast in the bowl. The yeast might be a little starved for nutrients until you put it in the must but it should become active and come back to life.

The reason I use a plastic cup is so that I can toss the cup and so I don't need to sanitize it. Oh, an I put the cups in an empty sink in case of overflow. It has happened once or twice.

Matrix

I know that Oskaar has mentioned in the past that Lallevin yeast are intended to be rehydrated in water or water/goferm. I recall reading somewhere that adding sugar to the rehydration can actually decrease the number of viable cells.

 

[Chevette Girl]

I know that Oskaar has mentioned in the past that Lallevin yeast are intended to be rehydrated in water or water/goferm. I recall reading somewhere that adding sugar to the rehydration can actually decrease the number of viable cells.

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.

 

[Medsen Fey]

Some studies have shown a small amount of sugar (like 50 g/L) in rehydration solution may be helpful.

 

[TheAlchemist]

Guess I just don't have enough Virgo in my chart...Sometimes I just throw the dry stuff on top of the must and see what happens...if it takes a little longer to get going, that's OK with me.