General yeast question

[Josh VanDerbeck]

In the last few beer kits I have bought the directions say to not rehydrate my yeast. The problem I have is that the package of yeast that comes in the kit say to rehydrate. What should I do, follow the kit instructions and not rehydrate or follow the instructions on the yeast package?

 

[camonick]

What kind/brand of yeast? Most dry yeast is designed to pitch straight into the proper temp wort without rehydrating now. I personally pitch all my yeast dry and get good results provided you maintain proper fermentation temps.

 

[Pappers_]

Either will work, the yeast will ferment your wort. That being said, the best practice is to rehydrate your yeast because, in summary, it will yield more intact, healthy yeast cells than not rehydrating. More healthy, vigorous cells means, potentially, better attenuation, fewer off flavor compounds, etc.

All that being said, I've done it both ways. I think it isn't critical because there is already a high yeast count in a packet of dry yeast, so losing some isn't as critical as it might be, depending on the beer and your other yeast management and fermentation practices.

Like a lot of life, the answer is maybe: it depends.

 

[camonick]

@Pappers_ is right... it really is just personal preference. Fermentis and Lallemand each include descriptions on their websites that says either way will work.
Lallemand—
“Rehydration of Nottingham in sterile water is recommended prior to pitching into wort in order to reduce stress on the cell as it transitions from dry to liquid form. For many fermentations, this stress is not significant enough to affect fermentation performance and flavor, so good results may also be achieved when pitching dry yeast directly into wort.”

Fermentis— SafAle US-05
① Direct pitching:

Pitch the yeast directly in the fermentation vessel on the surface of the wort at or above the fermentation temperature.
Progressively sprinkle the dry yeast into the wort ensuring the yeast covers all the surface of wort available to avoid clumps. Ideally, the yeast will be added during the first part of the filling of the vessel; in which case hydration can be done at wort temperature higher than fermentation temperature, the fermenter being then filled with wort at lower temperature to bring the entire wort temperature at fermentation temperature.

 

[Immocles]

I've used many different types of dry yeast and have yet to rehydrate any of them. As others have said, either process works

 

[BrewnWKopperKat]

What should I do, follow the kit instructions and not rehydrate or follow the instructions on the yeast package?

It depends on the brand/strain of yeast.

It seems reasonable to treat each brand/strain of yeast as being (relatively) unique. As of about a year ago (the last time I took a deeper look at product information sheets for the strains that I use):

• Fermentis has E2U: pitch it dry or rehydrate it, yeast is suitable for repitching
• Lallemand appears to lean towards rehydration for better results but pitching dry is ok, yeast is suitable for repitching
• Mangrove Jacks also seems to say lean towards rehydration for better results, but pitching dry is ok, yeast is not suitable for repitching.

Three brands - similar, yet different, recommendations.

edit: wording.

 

[AJinJacksonville]

Either process works with dry yeast...although, rehydrating without doing it in sterile water or carelessly could potentially increase the risk of contamination. As others have stated, dry yeast is typically over-saturated once it is introduced into the wort. Rehydrating may up the amount of cells, but you run the risk of introducing something that may screw stuff up. That being said, when I have used dry yeast, I have pitched directly into the wort and have never had any issues.

 

[seatazzz]

You're gonna find a lot of different opinions on this. Some rehydrate; some don't; some won't touch dry yeast but insist that liquid yeast is the way to go; some, like me, rehydrate dry yeast with chilled wort from the kettle. I've done all of them, but for the most part I think doing what is called a vitality starter (i.e., rehydrating with chilled wort) works best for me. Dry yeast tends to be cheaper than the liquid versions, although there's not as much varieties available as with, say, Wyeast or white labs. It all depends on what works for you, and the beer you're brewing, and your system, and a host of other variables; such as time, temperature, phase of the moon, etc. All joking aside, it really comes down to what works best for you and your beer.

 

[ike8228]

I actually do a starter with dry yeast the night before. Not so much to get the count up but to get it going faster. I found pitching dry takes 24-36+ hrs to start. When doing a starter I get results on average of 8 hrs. The sooner it starts the less likely a foreign bacteria can multiply before the yeast can take over. Once alcohol is present it makes it harder for other issues to happen. Also I can not speak factually on my own results, but it is supposed to attenuate better and produce a cleaner beer.

 

[DVCNick]

I actually do a starter with dry yeast the night before. Not so much to get the count up but to get it going faster. I found pitching dry takes 24-36+ hrs to start. When doing a starter I get results on average of 8 hrs. The sooner it starts the less likely a foreign bacteria can multiply before the yeast can take over. Once alcohol is present it makes it harder for other issues to happen. Also I can not speak factually on my own results, but it is supposed to attenuate better and produce a cleaner beer.

I'm pretty close to this... Often I do a starter just so I can pour some off for reuse next time. Costs me about $1.80 worth of DME to do a starter.
Now starters are still a minor pain, so recently I've been going back to direct pitching when I've been able to buy packets of US-05 for under $4. For ~$2.50 or less I'll just avoid the PITA of doing the starter and oxygenation.

As said above though, if you want speed out of the gates, I find that direct pitching doesn't come close to pitching a liquid starter into oxygenated wort. I would say my observed timings are similar to above; with a starter I have consistent outbound bubbles within 8 hours at most; sometimes blowing off at 24 hours. With a direct pitch to get to that same level of minor observable activity takes about 36 hours. Your beer is probably going to finish a day earlier with the starter if you're pressed for time.

 

[BrewnWKopperKat]

... the best practice is to rehydrate your yeast because, in summary, it will yield more intact, healthy yeast cells than not rehydrating. More healthy, vigorous cells means, potentially, better attenuation, fewer off flavor compounds, etc.

Can you share whose best practice it is & what is their supporting data is?

 

[ncbrewer]

Fermentis now recommends dry pitching part way thru the transfer to the fermenter, followed by filling the rest of the way. Since I top off with water, and the top-off temperature varies with the season, I emailed and asked about pitching on the foamy wort, followed by gently stirring. They answered that I was correct in thinking that pitching on foamy wort is not good. But they also cautioned against stirring immediately after pitching. For my situation, they recommended rehydrating.

 

[VikeMan]

Fermentis now recommends dry pitching part way thru the transfer to the fermenter, followed by filling the rest of the way.

That's what they recommend for commercial users, presumably because they can't "sprinkle" in a conical. For most users, I don't think they have changed their "sprinkle on top of wort" recommendation.

Since I top off with water, and the top-off temperature varies with the season, I emailed and asked about pitching on the foamy wort, followed by gently stirring. They answered that I was correct in thinking that pitching on foamy wort is not good. But they also cautioned against stirring immediately after pitching. For my situation, they recommended rehydrating.

I could definitely see sprinkling on foam as a problem. Their recommendation to rehydrate seems spot on. (IMO, rehydration is ok in any case.)

ETA: I know a couple of comm'l brewers who add dry yeast to the bottom of the fermenter, and then fill. I don't know if that's a great idea, but it does seem to work for them.

 

[BrewnWKopperKat]

that pitching on foamy wort is not good.

I could definitely see sprinkling on foam as a problem.

What specific off flavors would I expect to see from sprinkling dry on top of wort with foam? If there is an impact in attenuation, what measurable impact would I expect to see? Are the other measurable impacts, impacting the quality of the final product, that are mentioned?

 

[VikeMan]

What specific off flavors would I expect to see from sprinkling dry on top of wort with foam? If there is an impact in attenuation, what measurable impact would I expect to see? Are the other measurable impacts, impacting the quality of the final product, that are mentioned?

I don't know if there were measurable impacts mentioned. But I believe the issue would be that yeast cells sitting on top of foam won't rehydrate or perhaps would take too long to rehrydate, because they are not making direct contact with a reservoir of liquid.

Personally, if Fermentis says "don't sprinkle on foam," I'm going to believe that without digging further. Maybe @ncbrewer has more information from Fermentis on foamy impacts.

 

[Pappers_]

Can you share whose best practice it is & what is their supporting data is?

Chris White and Jamil Zainasheff in their book Yeast. John Palmer in How to Brew and both Zainasheff and Palmer on Brew Strong.

 

[BrewnWKopperKat]

Chris White and Jamil Zainasheff in their book Yeast. John Palmer in How to Brew and both Zainasheff and Palmer on Brew Strong.

Page numbers / episode numbers?

 

[Pappers_]

Page numbers / episode numbers?

Sorry, you're going to have to look that up yourself LOL Your tone says that you think I'm telling folks they should rehydrate. Perhaps you should re-read my post.

 

[BrewnWKopperKat]

Sorry, you're going to have to look that up yourself LOL

OK. Yeast is (c) 2010, How To Brew, 4e is (c) 2017. E2U for beer was introduced at Homebrew Con 2018 in Portland. Things change over time, books don't.

My questions were intended to find something measurable (or taste-able as in off flavors) in the final product that would support the claim that rehydrating yeast is either "better" or a "best practice". I've tried rehydrating a couple of times, found no difference. I'll consider trying rehydration again, but I need something measurable (or taste-able) in the final product next time around.

Sprinkle it on top, (or if you "fear the foam") sprinkle it in the middle, or rehydrate it. If yeast is expensive and liquid yeast doesn't ship well, make a starter (as dry yeast appears to ship with greater reliability in the summer). Just be sure to add yeast before closing the fermenter .

edit: updated to include information on when E2U was introduced from Demystifying Active Dry Yeast | American Homebrewers Association

 

[BrewnWKopperKat]

I could definitely see sprinkling on foam as a problem. Their recommendation to rehydrate seems spot on. (IMO, rehydration is ok in any case.)

ETA: I know a couple of comm'l brewers who add dry yeast to the bottom of the fermenter, and then fill. I don't know if that's a great idea, but it does seem to work for them.

There is an interesting thread over in the Beer Advocate forums: A Dry Yeast Rehydration Experiment. I linked to a specific reply as it has yet another email Q&A. The entire topic may be an interesting read as well.

 

[ncbrewer]

I don't know if there were measurable impacts mentioned. But I believe the issue would be that yeast cells sitting on top of foam won't rehydrate or perhaps would take too long to rehrydate, because they are not making direct contact with a reservoir of liquid.

Personally, if Fermentis says "don't sprinkle on foam," I'm going to believe that without digging further. Maybe @ncbrewer has more information from Fermentis on foamy impacts.

No - Fermentis didn't say what off flavors or problems would arise from sprinkling on foam. My guess is about the same as yours - it just won't rehydrate properly.

 

[Nate R]

In the last few beer kits I have bought the directions say to not rehydrate my yeast. The problem I have is that the package of yeast that comes in the kit say to rehydrate. What should I do, follow the kit instructions and not rehydrate or follow the instructions on the yeast package?

A pack of liquid yeast runs at least $8.99 right? Often up to $11.99 or more based pn shiping, etc. Then you have to deal with viability, etc.
I say (as a lazy, lazy, lazy man)- sprinkle 2 packets dry and go watch a game. At $2.99-4.99 a pack, it's about even.
Again- i am lazy. But this way you can avoid any potential contamination and save time.

 

[pc_trott]

I still consider myself a rank newb, but maybe I'm an incredibly lucky one! I've made seven five-gallon batches since my wife got me brewing equipment last Christmas, and I've started all of them with dry yeast. Since I use a carboy as my fermenter, I can't sprinkle all over the top of the wort. So I just pour the yeast from the envelope into the carboy, as like as not on top of the foam that I created by oxygenating the wort. The pile of yeast doesn't take much time, a matter of minutes, to dissolve the foam to get to the wort, and once there it dissipates quite rapidly. All seven batches have started bubbling away happily within 24 hrs, and I (knock on wood) haven't yet had a batch that wasn't quite tasty, according to the people I've shared them with. Add me to the lazy bum squad, but I don't think I'll be wasting any time with yeast starters in the foreseeable future. :>)

 

[SanJuanWorm]

I would chime in and say it also depends on time. If one has a few weeks, maybe go with a non-hydrated dry, directly onto the wort. I've brewed successfully this way, (but have another backup in the pipeline!)

Liquid yeast is great if your brewing schedule coincides with buying/picking up the yeast, letting it 'poof up' and then pitching within the same day or two.

Both work very well, and cost vs. time calculations have to come into one's particular brew day. Cheers!