Re-hydrating yeast kills?

[Stix]

There really is no reason to not rehydrate. I also use a little nutrient, like GoFerm when doing it. I have always rehydrated my wine yeast and although I primarily use liquid yeast, I have used dry on occasion and always rehydrate it. But then again, I would never use liquid without a starter either. Yeast is by far the most important ingredient in the beer, you might as well give it every advantage.

As far as liquid. I am with you all the way. That stuff is expensive! Want every advantage? Buy another packet of dry yeast for 2 bucks. Problem solved and no guessing.

 

[Dynachrome]

I have let it sit in the wort rehydrating for upwards of 2 hours. The other day I was making an IPA and it rehydrated during my 90 minute boil and my 30 minutes of cooling afterwards. By the time I was ready to pitch it was very thick and foamy and took off like a rocket.

That is an apt description of my results also without the stirring.

In fact, I placed one of my re-hydrated batches into really cool wort, about 48 degrees. As it warmed up, the fermentation really took off. I didn't document times, but it was surprisingly fast to start foaming. I'd say a couple hours.

 

[helibrewer]

My concerns with yeast are its health, not necessarily the numbers. The one caution I will say is to never use distilled or RO water to rehydrate...too much osmotic pressure.

 

[mobilecabinworks]

Um, aren't you "re-hydrating" when you pitch the dry yeast onto the wet wort?

Rick

Yeast have a harder time of rehydrating their cells with H2O to start processing fermentable sugars when the liquid they are immediately immersed in is loaded with sugar. This is due to osmotic pressure. By allowing them to replenish their "bodies" with water first allows them to process sugars faster and cleaner.

For example, you wouldn't go to the bar for a heavy night of drinking after walking out of a desert being completely dehydrated. You would want to rehydrate first in order to process your drinks. Maybe not the best analogy, but you get the point. Cheers!

Here's an link that discribes it pretty well: http://chemed.chem.wisc.edu/chempaths/GenChem-Textbook/Osmotic-Pressure-854.html

 

[Stix]

I am concerned for their health aswell. Though I have all but given up on dry yeast. I would never hesitate to have beginner brewers which this forum section is, to just toss it in. There is many things while hydrating that can kill off the yeast. In the beginning with all this new and exciting brewing going on this is one step that need not be done to have good beer.

As you progress and get more in tune and in the rhythm of the steps. Take the time and rehydrate. To me I still would not do it. I have made the same beer split into to batches and they both came out the same. Not scientific but enough for me to not worry about it. I have sense moved to starters and liquid.

Have a good night. I love this topic. One of my favorites.

 

[passedpawn]

As far as liquid. I am with you all the way. That stuff is expensive! Want every advantage? Buy another packet of dry yeast for 2 bucks. Problem solved and no guessing.

I think this is great advice.

 

[BansheeRider]

This thread has proven to be very informational. Thanks again everybody for your replies. I have already brewed my first beer without rehydrating the yeast and the fermentation was great. The initial fermentation was completed in 4 days according to my hydrometer readings. My next brew is the Octane IPA, ordered today from MidWest Supplies. I will try the re-hydrating method following the manufacturers directions. When I do this how will I know if the yeast did not survive? Do I have to take continuous hydrometer readings after a few days if I see no fermentation? Can I go and buy another packet of yeast and pitch in the wort even though there are dead yeast cells already in it?

 

[mammothkraken]

I only recently started rehydrating in wort and similarly Fermentis only recently suggested it...maybe they know something that we don't know about their product. I'm not discrediting anyone's opinion but I doubt they would advise you to rehydrate their yeast in wort if it produced undesirable results, why would you buy their product if that was the case?

 

[mammothkraken]

This thread has proven to be very informational. Thanks again everybody for your replies. I have already brewed my first beer without rehydrating the yeast and the fermentation was great. The initial fermentation was completed in 4 days according to my hydrometer readings. My next brew is the Octane IPA, ordered today from MidWest Supplies. I will try the re-hydrating method following the manufacturers directions. When I do this how will I know if the yeast did not survive? Do I have to take continuous hydrometer readings after a few days if I see no fermentation? Can I go and buy another packet of yeast and pitch in the wort even though there are dead yeast cells already in it?

Follow their directions and the yeast will survive. If your fermentor is sealed up well you will see signs of fermentation in the airlock and life will be joyous.

If by some freak chance you don't see signs of fermentation via airlock or hydrometer then go buy more yeast and pitch it in...but be sure to post here if said thing happens because I will be amazed.

Cheers!

 

[BansheeRider]

Follow their directions and the yeast will survive. If your fermentor is sealed up well you will see signs of fermentation in the airlock and life will be joyous.

If by some freak chance you don't see signs of fermentation via airlock or hydrometer then go buy more yeast and pitch it in...but be sure to post here if said thing happens because I will be amazed.

Cheers!

Is there a way to determine how much yeast survived and how much died?

 

[Dynachrome]

This is what mine looks like after a few hours:

Would one of you guys with more experience be interested in giving this a try and comparing your results?

It is kind of difficult to see, but some of the dry yeast is actually still dry and in a raft in the middle.

 

[mammothkraken]

Is there a way to determine how much yeast survived and how much died?

Unless you're brewing a high gravity beer I wouldn't even bother worrying about it. There is not an exact way to tell how much died and how much survived. In my experience even without rehydration I've always ended up with the same result... beer. Which I'm guessing is your primary concern!
Dry yeast has plenty of cells in a packet to pull you through a fermentation, otherwise people wouldn't buy it.

Go forth and make good beer!

 

[BansheeRider]

This is what mine looks like after a few hours:

Would one of you guys with more experience be interested in giving this a try and comparing your results?

It is kind of difficult to see, but some of the dry yeast is actually still dry and in a raft in the middle.

Is that just water and yeast? Looks like a little LDME is in those jars. Why hours vs 15 min like the instructions recommend?

 

[passedpawn]

Is there a way to determine how much yeast survived and how much died?

Yes. You'd need a microscope (400x or better), a hemocytometer (cell counter), and a stain to determine viability, which is the percent alive. Lots of brewers here do just that. It's not practical for every brew, but great for doing some studies.

 

[BansheeRider]

Yes. You'd need a microscope (400x or better), a hemocytometer (cell counter), and a stain to determine viability, which is the percent alive. Lots of brewers here do just that. It's not practical for every brew, but great for doing some studies.

Maybe I should've payed more attention in my HS science class lol.

 

[mammothkraken]

Maybe I should've payed more attention in my HS science class lol.

I should've said yes it's possible to look at a sample and estimate based off that...
Either way there is no simple test to perform as a new homebrewer to determine the exact number of your 230+ billion cells that survived.
I doubt you'll have any reason to question the viability of yeast for your early batches anyways.

 

[Dynachrome]

Is that just water and yeast? Looks like a little LDME is in those jars. Why hours vs 15 min like the instructions recommend?

I put a little table sugar in it. DME has been suggested by board members. I don't keep a stock on hand.

The reason for hours is that I cool my wort on the back deck. It takes longer and I have time, so I let the yeast do their thing for a while rather than just pouring them in at the last minute.

It does seem to greatly accelerate the start of fermentation as I think Mammothkraken said his results were.

Note to self. Pick up some DME. ...it could also be used to adjust Specific Gravity in a pinch.

 

[zeg]

You have not read enough about it then. It is a personal choice. Grow up. Its a game of chance both ways... Except damaged cells in wort can recover.

It's a personal choice only in the sense that you will probably get decent beer either way. It's completely misleading to call it a game of chance. I've yet to see any good evidence that rehydrating in wort is beneficial (if your links discussed any, I couldn't read them because neither worked), and several reputable sources claim and provide plausible explanations as to why it is probably harmful. The Cone article linked specifically claims that 100% of the viable yeast in a dry yeast packet remain viable after rehydration at the proper temperature in tap water.

I would never hesitate to have beginner brewers which this forum section is, to just toss it in. There is many things while hydrating that can kill off the yeast. In the beginning with all this new and exciting brewing going on this is one step that need not be done to have good beer.

Of all the things that one needs to do to produce good beer, rehydration is just about the simplest. If you're not capable of boiling water and cooling it to 105°F, I don't see how even an extract batch is going to turn out at all. While I'm all in favor of simplifying the process at the beginning, establishing bad habits is counterproductive, at least when the alternative is so straightforward.

The reason for hours is that I cool my wort on the back deck. It takes longer and I have time, so I let the yeast do their thing for a while rather than just pouring them in at the last minute.

While you may have time, at least according to the article linked above, letting the yeast do their thing is probably counterproductive since you're mostly letting them burn through the energizer reserves that were packed into the dry yeast packet.

 

[Demus]

It's a personal choice only in the sense that you will probably get decent beer either way. It's completely misleading to call it a game of chance. I've yet to see any good evidence that rehydrating in wort is beneficial (if your links discussed any, I couldn't read them because neither worked), and several reputable sources claim and provide plausible explanations as to why it is probably harmful. The Cone article linked specifically claims that 100% of the viable yeast in a dry yeast packet remain viable after rehydration at the proper temperature in tap water.



Of all the things that one needs to do to produce good beer, rehydration is just about the simplest. If you're not capable of boiling water and cooling it to 105°F, I don't see how even an extract batch is going to turn out at all. While I'm all in favor of simplifying the process at the beginning, establishing bad habits is counterproductive, at least when the alternative is so straightforward.




While you may have time, at least according to the article linked above, letting the yeast do their thing is probably counterproductive since you're mostly letting them burn through the energizer reserves that were packed into the dry yeast packet.

Zeg, I'm trying too but some folks just want to re-invent the wheel!! Why so much resistance to a 15 minute process supported by many experts is truly beyond me...

 

[Stix]

Boiling water does nothing to certain toxins in the water or a contaminated container. Temp probe could be off. Your all looking down a tunnel and a land full of fairy tales and unicorns. In the real world its not as perfect as you make it. Why worry about something that does not effect the outcome of your beer? Wait let m guess if you had a side by side you would nail it every time. Your making a big deal out of nothing.

You need not rehydrate to make a good beer. This is where you are wrong.

 

[BansheeRider]

Boiling water does nothing to certain toxins in the water or a contaminated container. Temp probe could be off. Your all looking down a tunnel and a land full of fairy tales and unicorns. In the real world its not as perfect as you make it. Why worry about something that does not effect the outcome of your beer? Wait let m guess if you had a side by side you would nail it every time. Your making a big deal out of nothing.

You need not rehydrate to make a good beer. This is where you are wrong.

If the final result is the same then why not do what the manufacturer recommends?

 

[passedpawn]

Boiling water does nothing to certain toxins in the water or a contaminated container. Temp probe could be off. Your all looking down a tunnel and a land full of fairy tales and unicorns. In the real world its not as perfect as you make it. Why worry about something that does not effect the outcome of your beer? Wait let m guess if you had a side by side you would nail it every time. Your making a big deal out of nothing.

You need not rehydrate to make a good beer. This is where you are wrong.

The thing you are missing here is that everyone on this site wants to make BETTER beer. If you have already perfected all the styles of beer you want to brew, that's great. But you're probably the only one.

You are 100% wrong about pitch rates not affecting the beer quality. Underpitching yeast results in several things that will make a beer noticeably less appealing.

 

[Stix]

The thing you are missing here is that everyone on this site wants to make BETTER beer. If you have already perfected all the styles of beer you want to brew, that's great. But you're probably the only one.

You are 100% wrong about pitch rates not affecting the beer quality. Under pitching yeast results in several things that will make a beer noticeably less appealing.

Your talking two different things. Under pitching is not tossing yeast on top of the wort. You can under pitch with any yeast... liquid, dry, rehydrated etc etc. I figured most would know the difference. I guess not. You missed my post if you think I do not want to make better beer.

Try to read my posts before such silly comments.

 

[Stix]

If the final result is the same then why not do what the manufacturer recommends?

Again read posts before such comments. I already explained.

 

[BansheeRider]

Again read posts before such comments. I already explained.

Don't get snooty with me all mighty one! I started this thread with the intention of learning. God forbid I missed a couple posts in a thread with over 80 posts.

 

[passedpawn]

Your talking two different things. Under pitching is not tossing yeast on top of the wort. You can under pitch with any yeast... liquid, dry, rehydrated etc etc. I figured most would know the difference. I guess not. You missed my post if you think I do not want to make better beer.

Try to read my posts before such silly comments.

If you kill half your yeast by not rehydrating, you are underpitching.

Did you read the information at the link I gave you earlier? Here it is:

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

 

[Stix]

Don't get snooty with me all mighty one! I started this thread with the intention of learning. God forbid I missed a couple posts in a thread with over 80 posts.

Where you see snooty? Sorry you do not read your own thread.

 

[Stix]

If you kill half your yeast by not rehydrating, you are underpitching.

Did you read the information at the link I gave you earlier? Here it is:

Again you did not read my posts. Pitch 2 was my advice. Its 2 bucks. With pitch calculators its easy.

 

[GotPushrods]

What are these "toxins" in my water, and how would they not also be in the wort I made with said water? Seems sprinkling 2 packets on toxic wort would be just as bad as sprinkling 1 packed on a little toxic water.

I think we've established that sprinkling 2 packets directly on the wort is the easiest route. But if rehydrating was too much "trouble", I probably wouldn't spend the other 5 hours on brew day either!

 

[passedpawn]

Again you did not read my posts. Pitch 2 was my advice. Its 2 bucks. With pitch calculators its easy.

I responded to that. I said it was good advice. I think it is you who is not listening to the rest of this thread.

If I told you that 99% of brewers have who rehydrate their yeast do so successfully and in a very easy manner, would you still continue to say it is a bad idea?