Hydrate or pitch dry?

[biochemedic]

Two words:

Add it to the rehydration water...

Check the data sheet for the particular yeast you're using...not every yeast calls for the same temp of rehydration water. I also like to attemper to within 10*F of the wort temp. The 20-30 min or so that I spend rehydrating the yeast is worth it if I get a full, healthy pitch. Proper pitch rates are the first step to good fermentation management...

I've posted this before, I consider it to be the pretty much definitive word on yeast rehydration, from Lalemand scientist Dr. Clayton Cone (replying to an e-mail question from a LHBS owner):

Dan,
I appreciate your dilemma It is a universal problem for those that market
Active Dry Yeast.

Let me give you some facts regarding rehydration and you can decide for
yourself where you want to compromise.
Every strain of yeast has its own optimum rehydration temperature. All of
them range between 95 F to 105F. Most of them closer to 105F. The dried
yeast cell wall is fragile and it is the first few minutes (possibly
seconds) of rehydration that the warm temperature is critical while it is
reconstituting its cell wall structure.

As you drop the initial temperature of the water from 95 to 85 or 75 or 65F
the yeast leached out more and more of its insides damaging the each cell.
The yeast viability also drops proportionally. At 95 – 105 F, there is
100% recovery of the viable dry yeast. At 60F, there can be as much as 60%
dead cells.

The water should be tap water with the normal amount of hardness present.
The hardness is essential for good recovery. 250 -500 ppm hardness is
ideal. This means that deionized or distilled water should not be used.
Ideally, the warm rehydration water should contain about 0.5 – 1.0% yeast
extract

For the initial few minutes (perhaps seconds) of rehydration, the yeast
cell wall cannot differentiate what passes through the wall. Toxic
materials like sprays, hops, SO2 and sugars in high levels, that the yeast
normally can selectively keep from passing through its cell wall rush right
in and seriously damage the cells. The moment that the cell wall is
properly reconstituted, the yeast can then regulate what goes in and out of
the cell. That is why we hesitate to recommend rehydration in wort or
must. Very dilute wort seems to be OK.

We recommend that the rehydrated yeast be added to the wort within 30
minutes. We have built into each cell a large amount of glycogen and
trehalose that give the yeast a burst of energy to kick off the growth
cycle when it is in the wort. It is quickly used up if the yeast is
rehydrated for more than 30 minutes. There is no damage done here if it is
not immediatly add to the wort. You just do not get the added benefit of
that sudden burst of energy. We also recommend that you attemperate the
rehydrated yeast to with in 15F of the wort before adding to the wort.
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. The attemperation can take place over a very brief period by
adding, in encrements, a small amount of the cooler wort to the rehydrated
yeast.

Many times we find that warm water is added to a very cold container that
drops the rehydrating water below the desired temperature.

Sometimes refrigerated, very cold, dry yeast is added directly to the warm
water with out giving it time to come to room temperature. The initial
water intering the cell is then cool.

How do many beer and wine makers have successful fermentations when they
ignore all the above? I believe that it is just a numbers game. Each gram
of Active Dry Yeast contains about 20 billion live yeast cells. If you
slightly damage the cells, they have a remarkable ability to recover in the
rich wort. If you kill 60% of the cell you still have 8 billion cells per
gram that can go on to do the job at a slower rate.

The manufacturer of Active Dry Beer Yeast would be remiss if they offered
rehydration instructions that were less than the very best that their data
indicated.

One very important factor that the distributor and beer maker should keep
in mind is that Active Dry Yeast is dormant or inactive and not inert, so
keep refrigerated at all times. Do not store in a tin roofed warehouse
that becomes an oven or on a window sill that gets equally hot.

Active Dry Yeast looses about 20% of its activity in a year when it is
stored at 75 F and only 4% when refrigerated.

The above overview of rehydration should tell you that there is a very best
way to rehydrate. It should also tell you where you are safe in adapting
the rehydration procedure to fit your clients.

Clayton Cone.

 

[jalc6927]

Rehydrated once in 80+ batches and had the worst yeast performance yet, probably because I don’t rehydrate.

I get great fermentation quickly when I pitch directly into cooled wort.

As stated before it’s a personal issue. Which ever way you decide to go stick with it

Consistency is far greater concern for new brewers then worrying about advanced techniques

I like easy to duplicate processes, but that’s me

 

[ancientmariner52]

Biochemedic, thank you for posting that info from Lallemand. A lot to ponder there.

 

[GHBWNY]

I get the rehydration (which should technically be "pre-hydration") school of thought, and I rehydrate. But what I could never figure out is why putting yeast in clear water before putting it into --- wort water --- makes any difference to the behavior of the yeast for the time it takes them to 'bloom'. The theory is that rehydrating "preps" the cell walls to make the transition to the wort easier. But since wort is water, and since the yeast don't start actively metabolizing for hours, what difference is a few redundant minutes in clear water beforehand going to make? Just sayin'.

 

[biochemedic]

I get the rehydration (which should technically be "pre-hydration") school of thought, and I rehydrate. But what I could never figure out is why putting yeast in clear water before putting it into --- wort water --- makes any difference to the behavior of the yeast for the time it takes them to 'bloom'. The theory is that rehydrating "preps" the cell walls to make the transition to the wort easier. But since wort is water, and since the yeast don't start actively metabolizing for hours, what difference is a few redundant minutes in clear water beforehand going to make? Just sayin'.

It's not "pre-hydration," it is literally re-hydration of dessicated yeast cells. The benefit has nothing to do with when the yeast start actively metabolising, it has to do with what's IN the "water." I would encourage you to read the information I posted above in more detail. If you put a dehydrated yeast cell directly in wort, there are a lot of things that can willy nilly get into and out of the cell without the yeast being able to control it, and that is damaging to the cell. Likewise if you put the yeast cell into distilled water (which by definition is without any dissolved solute), the reverse osmotic shock is also bad for cellular health.

On the one hand is a case of "too much," and on the other, "not enough." By getting the Goldilocks "just enough" with "normal amount of hardness" as Dr. Cone mentions (or as, I would contend, with the addition of GoFerm to regular water), you can optimize the environment such that you get the best number of viable yeast cells per gram of yeast. Better pitch rate = better beer (all other things being equal...)

 

[ancientmariner52]

Ok, you sold me. I suspect the reason I could never see a difference was because I wasn't rehydrating properly.

So, for myself, and anyone else who isn't at home with lab math: Let's say I have an 11gram pack of, for example, US-05. I'll boil my pretty good tap water, to sanitize and remove chlorine. Now, how much water, and how much Go-Ferm? That's where it all goes pear-shaped for me. I think I've been abusing my yeast for years.

 

[GHBWNY]

It's not "pre-hydration," it is literally re-hydration of dessicated yeast cells. The benefit has nothing to do with when the yeast start actively metabolising, it has to do with what's IN the "water." I would encourage you to read the information I posted above in more detail. If you put a dehydrated yeast cell directly in wort, there are a lot of things that can willy nilly get into and out of the cell without the yeast being able to control it, and that is damaging to the cell. Likewise if you put the yeast cell into distilled water (which by definition is without any dissolved solute), the reverse osmotic shock is also bad for cellular health.

On the one hand is a case of "too much," and on the other, "not enough." By getting the Goldilocks "just enough" with "normal amount of hardness" as Dr. Cone mentions (or as, I would contend, with the addition of GoFerm to regular water), you can optimize the environment such that you get the best number of viable yeast cells per gram of yeast. Better pitch rate = better beer (all other things being equal...)

I am living proof that you don't have to know a thing about brewing beer to brew beer.

 

[beermanpete]

Ok, you sold me. I suspect the reason I could never see a difference was because I wasn't rehydrating properly.

So, for myself, and anyone else who isn't at home with lab math: Let's say I have an 11gram pack of, for example, US-05. I'll boil my pretty good tap water, to sanitize and remove chlorine. Now, how much water, and how much Go-Ferm? That's where it all goes pear-shaped for me. I think I've been abusing my yeast for years.

Use 10 times as much water as you have yeast. I.e., 10ml/g.

 

[ancientmariner52]

Use 10 times as much water as you have yeast. I.e., 10ml/g.

Thank you! So 110ml water, and 1.1 g Go-Ferm to achieve 1%?

 

[beerlover77]

I don't normally see bubbling when I rehydrate - according to Danstar, foaming or lack of foaming isn't an indication of the activity of the yeast. You might be throwing away good yeast.

AT the start or perhaps before you mix you may see no signs of activity... When I stir after 15 min there are almost always bubbles and signs of life in my pyrex container especially with Danstar Nottingham, US-05 and 34/70. If your yeasties sink to the bottom and the liquid is clear it may mean they aren't working properly and there is no way I'm taking that chance. The mixture should be creamy and not grainy looking like when you first pour the yeast in.

I took the chance one time when there were no signs of activity and the beer didn't start fermenting so I re pitched. Coincidence maybe....

 

[biochemedic]

I am living proof that you don't have to know a thing about brewing beer to brew beer.

True, we can get away with a lot as homebrewers and still make a pretty good product...but I enjoy doing the fiddley bits with rehydration, and as an upside, I really do think I've seen that my beer and mead is better than it was...

 

[ncbrewer]

Use 10 times as much water as you have yeast. I.e., 10ml/g.

I don't feel that measuring the temperature of 1/4 cup of water would be accurate for me, so I rehydrate in a cup of water. I've never read any published info about whether this is ok, but I get good results. Has anybody seen a solid answer to this?

 

[Indoril]

There's a lot of good information in this Xbeeriment

Like some of the participants who made it past the triangle test, I perceived the rehydrated beer as being noticeably more malty and smoother than the dry pitch beer, which had what I can only describe as a subtle apple-like tartness, perhaps as a result of acetaldehyde from stressed yeast(?). I didn’t notice any differences at all in appearance or mouthfeel and neither have any real significant flaws that I could pick up.

 

[beermanpete]

I don't feel that measuring the temperature of 1/4 cup of water would be accurate for me, so I rehydrate in a cup of water. I've never read any published info about whether this is ok, but I get good results. Has anybody seen a solid answer to this?

Agreed, but you could pour off the extra 3/4 cup after reaching the desired temperature.

 

[browning348]

I did a brew yesterday and rehydrated a pack of US05 in just tap water that was at room temp. Glass was sanitized and covered, yeast added thirty min later. 8 hours later I have what seems like a strong fermentation starting.

 

[JDXX1971]

As you drop the initial temperature of the water from 95 to 85 or 75 or 65F
the yeast leached out more and more of its insides damaging the each cell.
The yeast viability also drops proportionally. At 95 – 105 F, there is
100% recovery of the viable dry yeast. At 60F, there can be as much as 60%
dead cells.

Somewhere on here (HBT) I was reading a thread that was saying re-hydrating in 95-105 was bad, too hot. So I told my chief yeast re-hydrator (SWMBO) who proceeded to roll her eyes at me, oh she who reads instructions. I tried to explain but that I had read it on the internet so it must be true, uh, no go. My wife has watched her little babies (the yeast) each time and knows when something is wrong she does it her way (the right way obviously) and we get good results.

We recommend that the rehydrated yeast be added to the wort within 30
minutes. We have built into each cell a large amount of glycogen and
trehalose that give the yeast a burst of energy to kick off the growth
cycle when it is in the wort. It is quickly used up if the yeast is
rehydrated for more than 30 minutes. There is no damage done here if it is
not immediatly add to the wort. You just do not get the added benefit of
that sudden burst of energy. We also recommend that you attemperate the
rehydrated yeast to with in 15F of the wort before adding to the wort.
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. The attemperation can take place over a very brief period by
adding, in encrements, a small amount of the cooler wort to the rehydrated
yeast.

My wife has always dealt with the dry yeast and has always had it ready in time, when being the variable. We never checked the temp of the yeast at pitch, most times it was probably about perfect (room temp) but past the 30 min window. I am going to pay attention to this next brew day.

 

[TANSTAAFB]

Fermentis gives instructions for both rehydration and direct pitching. I don't usually rehydrate because I've had excellent results without the extra step. If it's a bigger beer I will either rehydrate or pitch an extra pack. I usually pitch extra because it's easier and I'm lazy [emoji16]
That said, I also have very good brewing and sanitation practices,so I'm confident I'm giving the yeastie beasties a good meal! I aerate with pure O2 and I use Wyeast yeast nutrient because it's cheap insurance.

 

[TANSTAAFB]

Oh, and RDWHAHB [emoji482]

 

[ThirstyPawsHB]

I’m new to homebrewing, I’ve got 5 small stovetop batches under my belt, two kits and three just experimenting. All have been fairly decent. The last 3 I have hydrated my yeast, US05, and the precious two pitched dry. The yeast seems healthier and begins work sooner in the hydrated but all have turned out well IMO. My question is am I wasting time and risking infection by hydrating? Is it just as efficient to pitch dry? I’ve read both sides of the argument. TIA

I rehydrate in the wort, always, never an issue.