a handy tool to help with yeast rehydration

[NeverDie]

I ordered one of these:
https://www.amazon.com/gp/product/B07G9J4745/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
to help sustain the GoFerm rehydration formula at the recommended 104F degrees for 20 minutes (https://www.meadmaderight.com/yeast-handling.html).

Previously I used an electrically heated water bath with an inkbird to do it, but the setup was a hassle and this digital coffee cup warmer seems like it will be much simpler.

 

[RPh_Guy]

Why are you trying to hold the temperature?

I've never seen that recommended.

 

[NeverDie]

Why are you trying to hold the temperature?

I've never seen that recommended.

Not sure. I thought it was implied by the directions, but maybe not. I mean, for example, https://www.homebrewtalk.com/correctly-rehydrating-dry-yeast.html
says that "The water temperature must be between 95F (35C) and 105F (40C). This is very important. Dry yeast likes to be rehydrated very warm."
I read that as meaning that it should be kept in that temperature range during the rehydration, but I suppose you could maybe (?) also read that as just the temperature at which to start the rehydration.

After the 20 minute rehydration, I would remove it to ambient temperature and let it cool to within, say, 10F of less of the must temperature before pitching.

What is your method? Start a 104F and just let it drop however much during the 20 minutes?

 

[RPh_Guy]

What is your method? Start a 104F and just let it drop however much during the 20 minutes?

Yep. You're the first I've seen to try keep it that warm.

After 20-30 minutes you need to introduce sugar. Letting it sit longer without sugar starts depleting the yeast's energy.

 

[NeverDie]

After 20-30 minutes you need to introduce sugar. Letting it sit longer without sugar starts depleting the yeast's energy.

And you're doing that how? By mixing in some of the must (and thereby helping to equalize the temperature at the same time)? Or some other way?

 

[RPh_Guy]

I add must/wort to adjust the temp slowly (every 5 mins, no more than 10°F drop at a time).

https://www.meadmaderight.com/yeast-handling.html

After 20 minutes, you will need to temper the yeast slurry down within at least 18F of your must temperature. If the yeast slurry is any warmer than that, you risk killing most of your yeast due to cold shock. Make sure to take this step seriously otherwise, your fermentation will suffer. Tempering your yeast slurry can easily be done by adding an equal amount of must to the yeast slurry every 5 minutes until you are within that 18F range.

They say 18F drop is OK, but I've seen 10F from some sources and I try to be conservative.

 

[RPh_Guy]

Hm. 10°C is 18°F so that's probably what I saw.

https://scottlab.com/yeast-rehydration

 

[Blacksmith1]

I've been hydrating my yeast in a 50/50 mix of my must and water with a pinch of nutes at room temp with no problems. It's a little slow on the uptake but since it gets 12 hrs or more to fire up it works fine.

 

[RPh_Guy]

I've been hydrating my yeast in a 50/50 mix of my must and water with a pinch of nutes at room temp with no problems.

This works, but it's not really ideal because it drastically reduces viability.

https://bkyeast.wordpress.com/2013/03/13/more-on-yeast-rehydration/

 

[Blacksmith1]

I was thinking survival of the fitest. I guess I should try it the other way.

 

[Blacksmith1]

Good read. It makes sense. I guess I've been getting the activity by leaving it 12 or more hrs to build. It looks like using the other method will create a better, faster, stronger (6 million dollar) yeast.

 

[kh54s10]

I have always re-hydrated by starting with water at the proper temperature. I then just leave it on the counter for the 20 minutes. If it is 30 minutes I don't sweat things. Sure the yeast have depleted the nutrients added, but they aren't "starving" in that amount of time.

I have also stopped re-hydrating my yeast. Especially Fermentis yeasts. They now recommend that you do not re-hydrate their yeasts.

I have seen no difference in beers that had the yeast just sprinkled on the surface. If anything at all just a slightly longer lag time. Fermentation is almost always active by the next morning after pitching late in the afternoon the day before.

 

[Blacksmith1]

My primaries are usually done in 5 days due to temps. So speed of start isn't an issue. Getting a clean ferment is. From what I've been able to discern the more viable yeast at pitch the less likely to get fussels which is my main concern.

 

[kh54s10]

My primaries are usually done in 5 days due to temps. So speed of start isn't an issue. Getting a clean ferment is. From what I've been able to discern the more viable yeast at pitch the less likely to get fussels which is my main concern.

The concern with longer lag times is about limiting the time that a contaminate, wild yeast or bacteria, could start before the yeast would dominate.

I don't think that fusel alcohols are a product of how much yeast you pitch. More likely temperature of the ferment. Some say that you can get fusels from using TOO MUCH yeast. Not sure that is true.