Rehydrating dry yeast?

So i am curious does rehydrating dry yeast really make a difference? Is it like making a starter for liquid yeast?

The book "Yeast" says that as much as 50% of dry yeast dies if you don't rehydrate it first. They said it is because waking up in wort is too much of a shock compared with straight water. That's a good enough reason for me to rehydrate.

Follow directions on the dry yeast packet.

Rehydrate in 85-90 water for 20 minutes. Then stir and add a Tsp of OJ. Rest another ten minutes, stir and pitch!

never heard of adding a tablespoon of orange juice... what does that do?

i sometimes add small quantities of the wort to the rehydrated yeast after 20-30 minutes. i start off with a few spoonfuls, might end with adding a half-cup after some time. my unscientific thought is that this allows the yeast to start adapting to the sugary environment before taking the Big Plunge.

Yes, generally dry yeast should be rehydrated, but no starter.

When in doubt, go with the manufacturers recommendations. Most of them have quite good info available on the web. I always make it a point of reading their specs and recommendations -- especially before using or even ordering a new yeast.

I rehydrate and pitch. I wouldn't add OJ. I don't think it's enough to make a difference but if you feed the yeast simple sugar it loses the ability to metabolize more complex sugars.

Boil water, cool, once below 90 drop in yeast for 20 minutes. Before pitching put spoonfuls of wort into the yeast - same as you would do when tempering an egg mixture... (balancing the temp to not cook the egg/shock the yeast. When it's within a few degrees of the rest of the wort, pitch.

This is a pretty good video on how to re-hydrate yeast.

+1 for the vid - It is similar to the one I used the first time.

Also, as far as does rehydrating make a difference, I have to say YES. The one time I did this, fermentation took off when comared to the 'ole sprinkle and seal.

Slightly off topic, but I have a pack of dry yeast that has a use by date of over a year ago. If I wanted to use it, should I make a starter, or simply rehydrate it?

Water only. Dried yeast cell walls are leaky and sugars from wort or acid from juices, etc will kill them.

And don't expect a layer of foam to form. It might, but that has nothing to do with the viability of the yeast.

asidrane said:

Slightly off topic, but I have a pack of dry yeast that has a use by date of over a year ago. If I wanted to use it, should I make a starter, or simply rehydrate it?

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I personally would not use it. I would rather buy a package of dry yeast that is in date than risk having my beer not ferment properly. Also a package of dry yeast is pretty cheap. Why risk it; but that's just me.

I follow directions on the dry yeast packet as well but I also use a stir plate for 10-20 Minutes is this ok seems to work ok ???

I've never rehydrated dry yeast (Safale US-05 primarily) and have had great results. Recently had an Imperial Stout go from 1.091 to 1.016 (10% abv) with it; 2 packs.

sweetcell said:

never heard of adding a tablespoon of orange juice... what does that do?

i sometimes add small quantities of the wort to the rehydrated yeast after 20-30 minutes. i start off with a few spoonfuls, might end with adding a half-cup after some time. my unscientific thought is that this allows the yeast to start adapting to the sugary environment before taking the Big Plunge.

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The yeast really take off w/ the sugar in the OJ & it adds no flavors.

I haven't done a comparison, as I've always rehydrated. All of my beers have launched into active fermentation within a few hours of pitching, and it only takes a couple of minutes' attention during time when I'm waiting around anyway. Since the manufacturers all fairly strongly recommend it in their detailed instructions, this seems like a good idea.

Most I use recommend against adding wort, though I think some may say it's ok after the initial rehydration period. I've never bothered. I usually do what they recommend and sprinkle the dried yeast evenly over the warm, sterile water first, then stir for a while.

Based on the reccomendations here, I think I will try to rehydrate (US-05) when I brew this weekend (never have before). Based on the co website, for the volume of watre to use, they reccomend 10x the package weight. If my math is correct, that is only about 4 oz of water. Does that seeem correct? How much water do you use?

kevinb said:

Based on the reccomendations here, I think I will try to rehydrate (US-05) when I brew this weekend (never have before). Based on the co website, for the volume of watre to use, they reccomend 10x the package weight. If my math is correct, that is only about 4 oz of water. Does that seeem correct? How much water do you use?

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Check out this video:

I pitch dry and the beer finishes like it should.

Of course, I do say a lot of really positive things to my yeast packet before I pitch. My transcendental meditation guru / brewing coach told me the positive vibrations will stimulate the yeast at the proper resonant frequency required for maximum yeast viability and optimal fermentation.

My guru has a podcast too, but the guy travels to other dimensions. Let's see Jamil do that!

kevinb said:

Based on the reccomendations here, I think I will try to rehydrate (US-05) when I brew this weekend (never have before). Based on the co website, for the volume of watre to use, they reccomend 10x the package weight. If my math is correct, that is only about 4 oz of water. Does that seeem correct? How much water do you use?

Click to expand...

Yes, so about 1/2 cup. (Based on the thumbnail, the video has you start with 3/4 cup, which is fine, plus you'll lose a bit from boiling.) It's not much, especially after measuring out gallons and gallons for the brew, but it's enough.

The pep talks are also critical, whether you pitch dry or rehydrated!

I've done both, I feel rehydrating leads to less lag time, plus it's easy. Lately (last 6-9 months) I sanitize a small container, add room temperature bottled water from a sealed bottle (about half cup), add the yeast, put sanitized lid on container and let it sit till the boils done and wort is cooled. Has worked great for last 10 brews, and ferment is usually going in 6-8 hours.

The last couple batches, I wound up using Giant Eagle spring water for the re-hydrate as well. Pitching at high krausen,they took off in about 3 hours! That's a new one for me in a couple years. I finally figured out what's doing it...

I use US-05 regularly and have not re-hydrated the last 40ish batches. Never had a stuck fermentation and my FGs routinely get down to 1.010. Now, I am careful not to under-pitch and generally will use 2-packs in beers over 1.065. Yes, re-hydrating is easy, but to me it is just not necessary and until I have a reason to do so, I'll just keep tossing the yeast in there dry. And yes, I believe that liquid yeast, starters, etc. are unnecessary for most beer styles. Nothing wrong with using US-05/04 for most of your brews!


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My $0.02.

Here's what I do (and while I do have one, a science degree is unncessary for this procedure):

Put about half a cup of lukewarm tap water in a bowl.
Open package of yeast.
Sprinkle on top.
Let sit while I cool my wort and transfer to the primary carboy.
Gently stir the now (completely or almost completely) rehydrated yeast.
Pour into the carboy.
(Optional: ) Swish the carboy around to mix.
Fit airlock and put somewhere safe.

I have never had dry yeast not wake up or being slack, and the one infection I've had is one I can trace back to a sanitation issue in my secondary carboy.

I think yeast is being babied too much; while it's a fragile organism, I find that it can take a punch and not go down crying. Unless you have sanitation issues, even a less-than-ideal pitch should be able to ferment your wort.

Of course, YMVV and I'm talking about more or less everyday brews instead of high-grav, sours, and weirdly formulated brews.