Re-hydrate the yeast or sprinkle it on?

[jfr1111]

"Skipping rehydration kills about half the cells piched. Besides having only half as much yeast as is needed, the dead cells immediately begin to break down and affect the beer flavor."
-Yeast, by Chris White and Jamil Zainasheff (page 146)
I do understand your point about recommendations for new brewers, but rehydrating your yeast will be beneficial to your beer.

Not that Chris and Jamil don't know their stuff, but "kills about half the cells" ? This gets thrown a lot around without any cited sources to back it up. I get that the yeast cells cannot properly control what passes through their membrane and that the sugary wort is not the best thing for them. I also listened to the podcast where Jamil talks about following the recommendations given to COMMERCIAL and not HOMEBREWERS for dry yeast. Well, guess what ? The instructions on the fermentis website for all their strains specifically calls for either sterile water OR wort. They also specify you can pitch directly if the wort is above 20C.

I personally always rehydrate ever since my second run in with bad notty, just to proof it, so I have no ax to grind. It's just that I see the 50% quoted all the time and it seems arbitrary to me.

 

[passedpawn]

Not that Chris and Jamil don't know their stuff, but "kills about half the cells" ? This gets thrown a lot around without any cited sources to back it up.

Chris White is the source, IMO. I guess it's understood that anything that guy says is backed by science.

 

[BradleyBrew]

Not that Chris and Jamil don't know their stuff, but "kills about half the cells" ? This gets thrown a lot around without any cited sources to back it up. I get that the yeast cells cannot properly control what passes through their membrane and that the sugary wort is not the best thing for them. I also listened to the podcast where Jamil talks about following the recommendations given to COMMERCIAL and not HOMEBREWERS for dry yeast. Well, guess what ? The instructions on the fermentis website for all their strains specifically calls for either sterile water OR wort. They also specify you can pitch directly if the wort is above 20C.

I personally always rehydrate ever since my second run in with bad notty, just to proof it, so I have no ax to grind. It's just that I see the 50% quoted all the time and it seems arbitrary to me.

I agree 100%. I hydrate sometimes.. other times I just pitch.. typically depending on gravity. I just don't understand why some brewers have to get on their "high horse" about re-hydrating... if it works for you fine.. If direct pitching results in good beer for the individuals that goes that route that's fine too. Its always a different % off yeast this is off'ed when added directly to the wort blah, blah, blah. As I mentioned before if someone is just starting then direct pitch. Once you are accustomed to sanitizing then go for rehydrating or yeast starters, etc.

Just because I scientist says something doesn't mean its a scientific law. "Scientist" once believed the world was flat. Even though Dr. Chris is a multi millionaire from cultivating yeast.

 

[jfr1111]

Chris White is the source, IMO. I guess it's understood that anything that guy says is backed by science.

That very well might be, but it doesn't change the fact that a company that actually manufactures dry yeast has rehydration protocols using wort in their datasheets. Danstar specifically says not to use wort, because of loss of viability. But they still don't give percentages... Does it changes with OG ? Temperature ? Strain ? Is it always "about half" ? This is what I'm wondering about.

 

[BradleyBrew]

That very well might be, but it doesn't change the fact that a company that actually manufactures dry yeast has rehydration protocols using wort in their datasheets. Danstar specifically says not to use wort, because of loss of viability. But they still don't give percentages... Does it changes with OG ? Temperature ? Strain ? Is it always "about half" ? This is what I'm wondering about.

+ 1 agreed... just stating "50%" is a very vague arbitrary figure. Thats like saying rehydrating yeast will yield 100% of all viable yeast in a packet.... I'm sure some yeast do not survive the rehydration process.

 

[insubordinateK]

It seems intuitive that more yeast cells would survive water rehydration vs wort rehydration; however, I will agree with above posts that I would like to see more data before I believe the 50% theory. From my own experience both ways will work.

Although I do rehydrate in water to error on the side of caution.

 

[Germelli1]

The only time I pitch dry yeast is in a low gravity beer like with a 1.035 mild with nottingham. Then I wash that to keep a stock of the yeast in my fridge. Even if the cells die, I would still be pretty close to a good pitching rate. At the same time I always keep a packet on hand in case a starter fails. So I donot have any emotion invested to either side, but have a question along the lines of others in this thread.

I would also like to see what the 50% figure is based on...if a packet is 80% viable (meaning 10% died in dehydration, storage, shipping, handling, etc) then is that 10% that is already dead factored into the 50%? So with the 50% figure are you saying you would have only 40% of what is viable in the packet? Or still 50% of what is viable.

Man, the question in my head is a lot harder to explain than I thought!

 

[unionrdr]

My head's been hurting thinking of all the times I've tried to explain this stuff since I started brewing again. Re-hydrating & small starters for sry yeast is no more harmful than it would be to liquid,in my experiments,anyway. I can take a 7g packet of ale yeas,re-hydrate it in 1.5C water with 2tsp dextrose,& make it perform as well as 11.5g US-05 pitched dry. Maybe a tad better. But put that same sachet in a 1.5C starter with 1/4C DME,& you damn well better have a blow tube rigged up for 1-4 days! This version works very well indeed,so never mind what some scientific guy with a doctorate says. They can be wrong too. There's no shame in that whatsoever.
Some folks on here just need to stop flaming others with someone else's knowledge. Experiment,see for yourself what works well,what works so-so,& what out & out blows donkey junk.

 

[JuanMoore]

Dry yeast contains so many cells per gram that pitching dry usually has no ill effects even though many of the cells are killed off. The time when there would be a noticeable difference is a very high gravity beer, where pitching dry would result in underpitching, and rehydrating would help keep pitching rates within range.

Not that Chris and Jamil don't know their stuff, but "kills about half the cells" ? This gets thrown a lot around without any cited sources to back it up..........
Does it changes with OG ? Temperature ? Strain ? Is it always "about half" ? This is what I'm wondering about.

One oft cited source is a study performed by Dr Clayton Cone who is or was the lead biologist for Lallemand. Rehydration temperature was found to have a profound effect on viability, sometimes lowering to only 40% when using 60F water as opposed to 100% with the reccomended 95-105F water. The higher the OG the more concentrated the sugars passing through the cell walls are, and the more damaging it is to the yeast. To what degree, I don't remember. I have heard that Dr Charles Bamforth who heads the Master Brewer program at UC Davis has also done some studies with similar results, but I can not confirm this.

Thats like saying rehydrating yeast will yield 100% of all viable yeast in a packet.... I'm sure some yeast do not survive the rehydration process.

According to the studies by Dr Clayton Cone 100% was pretty easy to achieve using fresh yeast as long as the water temp was within the 95-105F range. To stress, this was using FRESH yeast, dry yeast viability decreases ~4%/year if stored at fridge temp, and ~20% /year if stored at room temp. I'm sure you're right that "some" cells die since we're dealing with billions of cells, but if rehydrated properly it should be an insignificant amount.

 

[GreenDragon]

If I'm fermenting in a carboy then I rehydrate just because every time I try to sprinkle it in dry I always get some on the neck of the carboy and I'm worried that could eventually cause an infection.

When I ferment in a bucket I don't bother though.

 

[Revvy]

Not that Chris and Jamil don't know their stuff, but "kills about half the cells" ? This gets thrown a lot around without any cited sources to back it up. I get that the yeast cells cannot properly control what passes through their membrane and that the sugary wort is not the best thing for them. I also listened to the podcast where Jamil talks about following the recommendations given to COMMERCIAL and not HOMEBREWERS for dry yeast. Well, guess what ? The instructions on the fermentis website for all their strains specifically calls for either sterile water OR wort. They also specify you can pitch directly if the wort is above 20C.

I agree....this is the new boogeyman that folks toss around too quickly now...(Don't forget even John Palmer has been wrong about stuff.)

Chris may be the King of liquid yeast, but that doesn't mean he necessarily has a lot of experience with dry OR even wants folks to use it over HIS product.

I maintain the sprinkling on top, and letting it sit on the surface of the wort IS rehydrating with wort....no different than if it were in separate container. I use fermentis, fermentis SAYS you can pitch onto the wort.....

Alternatively, pitch dry yeast directly in the fermentation vessel providing the temperature of the wort is above 20C (68F). Progressively sprinkle the dry yeast into the wort ensuring the yeast covers all the surface of wort available in order to avoid clumps. Leave for 30 minutes and then mix the wort e.g. using aeration.

That's good enough for me..

 

[AnOldUR]

Activator™
The Activator™ has a minimum of 100 billion cells of pure, ready-to-pitch yeast, plus an internal nutrient packet. The Activator™ is designed to inoculate five gallons of wort (up to 1.060 SG) providing the pitching rate recommended by professional brewers.

That's good enough for me..

 

[zyx345]

Just brewed Brewcraft's Rogue Dead Guy kit. OG came in at 1.070 and used Safale US-05 and rehydrated using this method:

 

[passedpawn]

Just brewed Brewcraft's Rogue Dead Guy kit. OG came in at 1.070 and used Safale US-05 and rehydrated using this method:

It's easier if you just use microwavable tupperware container with a lid and let it cool naturally (in the mic). I've put it into the fridge, and every time I let it get too cold

Also, although adding yeast at 100 is perfect, after re-hydration you should slowly chill the re-hydrated yeast to the same temp as the beer you are inoculating (attemperation). Easiest way is to just slowly add small amounts of the wort that will be inoculated. Warm yeast into a cold wort will cause many of the yeast to produce petite mutants that will never grow or ferment properly and will cause them to produce H2S (from Dr. Clayton Cone).

(finally, boiling in a microwave does not sterilize; pet peeve of mine).