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Do you ever HAVE to rehydrate dry yeast?

I’m right this very minute boiling wort for the Saison au Miel small batch kit. The directions, like all the kits I’ve used so far, simply say to pour half of the dry yeast packet onto the cooled wort in the fermenter. However, the back of the yeast packet (Dupont Saison-style) it says to rehydrate the yeast. I honestly don’t know if the other yeast packet from the other kits said this or not. At any rate, I’m a little confused as to whether I should or should not do this.

No, you don’t have to.

Some argue that you should though. I haven’t seem much if any difference in lag time, FG, flavor when I choice to not rehydrate vs rehydrating.

You CAN rehydrate. Like many other aspect of brewing you’ll get different opinions.

I’ve used dry yeast maybe a dozen times and never once rehydrated it. A few times it started up within a few hours, all the other times it started overnight. I pitch one pack in 5.25 gals if it’s under 1.060 and 2 if it’s a bigger beer.

I used to re-hydrate for every batch, then I started just sprinkling on the top to see if I could see any differences. I never did see anything noticeable so I just sprinkle on top.

OK sounds good. I’ve had decent luck so far just sprinkling it, so that’s what I’ll do here.

Thanks

I’ve never rehydrated and never had any noticeable issues. Fermentation takes off right away.

Ditto.

The manufacturer normally advises the proper process for their yeast, and the packs I’ve been using for years say right on them to sprinkle directly on top of wort. While there is no single rule, I have read that most of the dry yeast today is created ready to hit wort directly and is made for that. In the past that might not have been the case. I’d follow the manufacturer’s directions if available. This is a place in our hobby that you’d really have a hard time doing anything wrong :slight_smile:

I’ve done both and both ways will work. The owner of my LHBS does not rehydrate. He makes good beer. Two guys in my home brew club just opened a small micobrewery/tasting room. They pitch dry yeast as they are aerating. They make excellent beer.

I personally don’t think it matters either way.

[quote=“dobe12”]I’ve done both and both ways will work. The owner of my LHBS does not rehydrate. He makes good beer. Two guys in my home brew club just opened a small micobrewery/tasting room. They pitch dry yeast as they are aerating. They make excellent beer.

I personally don’t think it matters either way.[/quote]
I think it only matters if you are on the edge, cell-count wise. You will kill a significant number of cells from shock when they flood themselves with high sugar wort as they rehydrate, but there are so many cells in a pack that only matters if you are brewing a strong beer or making a bigger batch, both of which should get higher numbers of cells when pitching. If you are doing a 1 gallon batch as it appears the OP is, it would be VERY hard to see half a yeast pack as being on the edge. Go ahead and just sprinkle it on top.

DanStar

Why is rehydrating the dry yeast before pitching important?

Dry beer yeast needs to be reconstituted in a gentle way. During rehydration the cell membrane undergoes changes which can be lethal to yeast. In order to reconstitute the yeast as gently as possible (and minimize/avoid any damage) yeast producers developed specific rehydration procedures. Although most dry beer yeast will work if pitched directly into wort, it is recommended to follow the rehydration instructions to insure the optimum performance of the yeast.

Fermentis

Rehydration

Before dry yeast can start fermenting, they need to absorb the water they lost during the drying process.

Yeasts are living organisms and rehydration temperature is critical for good yeast performance.

Fermentis recommends that top fermenting (ale) yeasts are rehydrated at a temperature between 25-29°C (77-84°F) and that bottom fermenting yeasts (lager) are rehydrated at a temperature range of 21-25°C (69-77°F).

Rehydration is done in a vessel outside the fermentor. The objective is to reduce the lag phase : the time necessary for the yeasts to start fermenting sugars to alcohol after inoculating the wort.

Rehydration is a simple procedure.

Rehydrate the yeast in 10 times its weight of water or wort. Gently stir. Allow a 30 minutes rest. Pitch the resultant cream in the fermenter.

Lallemand

http://www.scottlab.com/uploads/documen ... lemand.pdf

[quote=“GeneticBrew”]Although most dry beer yeast will work if pitched directly into wort, it is recommended to follow the rehydration instructions to insure the optimum performance of the yeast.[/quote]How can you trust anything a company says if they don’t know the difference between “insure” and “ensure”? :wink:

Scientists are so rarely grammarians or strong spellers - thank goodness that some of us attended liberal arts schooling. :mrgreen:

What worries me more (and I hope they carry good insurance!) is that I seem to recall conflicting info on what the water make up should be. Is RO going to be harmful? Or too much mineral content? I see that link was for wine, but assuming you do the same ‘tempering’ of warm re-hydrated yeast with small additions of pitching temperature wort - that just seems like more mucking around and more chance for infection.

For me, the simplicity of ‘sprinkle’ has won over the potential for higher viability with re-hydrate, and just seems very low risk.

COMPROMISE? - Ahhh, one thing I have thought about, inspired by my extract & partial boil days, and observing the strong stratification of the concentrated wort and the top-off water - what if you poured ~ 2 cups of boiled and cooled water carefully on top of the wort, and sprinkled the yeast on that? A few degrees warmer than the wort would also help keep it on top. I bet it would stay pretty low gravity for 20 minutes to give the yeast a chance to adjust. Then shake it to aerate as normal.

-kenc

A pack of dry yeast has about twice the number of cells as a pack or vial of liquid yeast. If you don’t rehydrate, you kill about half the cells in a dry yeast pack, bringing the cell number down to that of a liquid yeast packsge. So, If you feel that using liquid yeast without a starter is fine, then you’ll probably feel that pitching dry yeast without rehydration is fine.

That is true only if the liquid yeast is very fresh. I can never get very fresh liquid yeast, and I would never think of pitching without a starter. But with dry yeast, there are many times I know that sprinkling will work fine. If I’m making a bigger beer (1.060 or more for 5 gallons), I would always rehydrate dry yeast.

I always rehydrate…my friend John Palmer told me so :slight_smile: Plus I like smell of it.

There’s not a lot of room on the back of a yeast pack to give a lot of info on rehydrating, but all the dry yeasts I’ve used have web sites that give plenty of info on pitching and rehydrating.

If you read the instructions you must remember this important point: If you read the instructions, you must not EVER admit it or you could have your man-card revoked!

I had a beer judge ask me if I had rehydrated my dry yeast in a beer I had made, and I said no. He then told me " I thought so", then preceded to tell me he could taste a sweetness that he picked up in the taste and told me if I had rehydrated it, that wouldn’t be there. I thought he was “full of it” but later I wondered if he really knew what he was saying. Personally my tasters aren’t that sophisticated
so since then I rehydrate just for kicks, what the heck I got time to do it.

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