Why Rehydrate And Pitch Dry Yeast Warm?

[InCider]

Baker ey?

Bet you made alot of dough.

Not even points for trying on that one Bugman <_<

He's just trying to get a rise out of him...

 

[SpillsMostOfIt]

He's just trying to get a rise out of him...

Oh... Give it a rest... A man's got to make a crust.

 

[Screwtop]

Baker ey?

Bet you made alot of dough.

Told a publican to "shove his pub up his arse" once, he'd never heard that before either :lol:

 

[ohitsbrad]

Thanks guys for so many responses. A lot of different opinions and experiences. I have rehydrated dry yeast whenever I've used it so far, but am bound to try just sprinkling it in soon enough. I use two packets for around 20 litres. It seems as though rehydrating the yeast at warm temperatures is not an issue; not the same process as making a starter with liquid yeast.

I am an extract brewer, done a couple of partial mashes, and have got most of my equipment together to begin all grain brewing.

 

[PistolPatch]

Evenin',

Had an email tonight on this thread. When I answer someone's email, I use a different colour from their question. I thought that me copying some of my answer here may be useful. Hope so! My replies to this email are written in red...

Anyhow, just read your post on re hydrating yeasts and thought it was good, I rehydrate mine. I was fairly smashed when I wrote that post lol. Had been at a Freo pub for several hours :blink: Can't even remember why or when I started but just do now, guess I like to see it kick up first. Anyway interested in your methods on splitting a dry pack 6 ways, guess it would be similar to liquid methods people use.

I used to not only re-hydrate but acclimitise the yeast gradually to the wort. Its a bit of fun but it is time-consuming and hard to cool the wort quickly etc, etc. As I never noticed any diff in the end result, I have stopped doing it.

I reckon the old building up starters is a hell of a lot of work too and I have never done it. Certainly far more work than the above. So what I do now is just harvest the yeast cake. Do this as follows...

Pitch the yeast whether it be dry or a smack pack into your brew and let it ferment out as normal.

Once you have bottled, kegged or racked your fermenter, youll have the yeast cake left.

Prior to this have a PET bottle of cooled boiled water (I often just use water straight from the tap but best to play it safe) at the same temperature as your racked beer. For example, if you rack into a secondary, then youll need that PET bottle to be at y our fermenting temp. However if, like me (and ThirstyBoy,) you chill your primary and then keg it via a filter then youre cooled boiled water needs to be at say 2 degrees.

Once youve racked your fermenter, open the lid and pour in the cooled boiled water. Swish it all around and then drain that slurry into one or two no-rinsed PET bottles.

Chuck the resulting bottle/s of slurry into your fridge. (Also chuck a bottle or two of cooled boiled water in the fridge as youll need them later.) The water and yeast will separate within a few hours so next day, drain off the water, and add an equivalent amount of cooled boiled water from the other bottles of water you had in the fridge.

Repeat this process until the water you drain off runs clear.

Personally, I think the draining off the water is probably unnecessary. Therefore I sometimes do it and sometimes I dont. Its actually probably better to be non-lazy with this though unless you are brewing every week. (Im just thinking back and maybe it was just my laziness that made me have to buy new yeast after 7 or 8, possibly 9 months.)Then again, the more transfers you do then the higher risk of contamination I suppose. Who knows lol!

Anyway, using this method, I have been able to keep a sachet of yeast going for over 7 months, brewing every 3 weeks on average but sometimes 8 weeks between brews. So this is actually splitting the packet more than 6 ways!

It works well and anyone who knows me will know that I am the hardest critic on my beers.

When it comes to brew day, get your bottle of yeast out of the fridge (it will now have a layer of clear water above it.) Let it reach room temp while youre brewing. Before you go to pitch it, pour off the water into a glass. Smell it and taste it. Youll readily know if it is not right.

Assuming it is right, I usually add some wort out of the fermenter when Im taking a hydrometer reading just before pitching and add that to my PET bottle of yeast. I give it a good shake. Careful! Open the lid slowly otherwise youll have yeast everywhere. Then I just pour the mix into the fermenter.

I usually throw about 200mls of slurry in each 23lt batch and it takes off pretty much straight away.

Had a yarn (via PM) with ThirstyBoy about different ways of splitting liquid yeasts, I have done one using Batz method on AHB but I don't think it kicked of like it should have. Yep, all too hard for me but Im sure Ill have a crack one day just for fun. ThirstyBoy and Batz know what they are talking about though so it is worthwhile to pay special attention to their posts.

If I get time later think I might put on one of my kits n bits still in the cupboard, Coopers Bavarian lager with a Wyeast Bavarian lager yeast. Not sure what extras yet. [Name], if you are getting drinkable kits, youll cream it on the AG. Its hard to bugger a good recipe up. The only awful AGs I have made have been with SO-4 or this last lot of crappy US-56 which in the past has been totally reliable. Im actually currently trying to back-track where the US-56 went wrong. It is possible that I ditched the right yeast and kept the old yeast. Its bloody hard to back-track 6 or 8 weeks though. I have now started labelling my yeast bottles in the fridge with a date. Pretty obvious stuff but its funny how much we think we will naturally remember 4 6 weeks down the track lol!

 

[pint of lager]

Brad, shocking yeast thermally is definitely a problem. Someone in the chatroom had attended one of the sessions when a representative of either Wyeast or Whitelabs came to town and asked them about rehydrating and shocking.

I don't remember the exact response, but it was ok in one direction and bad in another. I suspect that yeast quite happily work in the range of 18-35. We keep them in a much narrower range where the flavours that we want are produced or reduced.

The range of responses are interesting. Screwtop's, MHB's and other observations are what makes this and other forums tick.

After much yeast work here, including alot of work with a pressure cooker, slants and petri dishes. Stepping up and attention to sanitation are essential when working with small quantities. When I use dried yeast, it is snip and sprinkle.

PP, it is time to read the most recent thread on note taking. No more blaming the yeast for poor results when you have used the same sample for umpteen brews.

If anyone is considering saving and washing yeast slurry, there is an excellent thread here on AHB written by Chiller. Plus, one of the yeast manufacturers covers it comprehensively on their website. Like any yeast work, sanitation is very important. Washing with plain tap water is not on and prone to poor results.

 

[SJW]

Why Rehydrate And Pitch Dry Yeast Warm?

Good question. Unless you live in a sub zero climate or the pack of yeast is old there is no reason I have found, in all my years of brewing, that you should need to re-hydrate yeast. It would just be another avenue for infection if your somatisation is not 100%.
I have done side by sides with dry and re-hydrated and have found no compelling evidence that this step is required. And I am sure there will be a thousand replies on the contrary, but that my opinion.

Steve

 

[pint of lager]

Link to Chiller's washing yeast thread.

Use this info if you want to wash yeast. This is much more detailed and also differs in which layer to save.

Either Whitelabs or Wyeast used to have an article on yeast washing, but have been browsing their site and can only find the acid washing article.

They also suggest not using slurry beyond 6-7 generations/brews as the risk of infection and mutation is too high.

 

[chovain]

For dried yeats, like Mark, I advise my customers to pitch dry.

I've tried all different ways, but for the record this is how I now do mine, which is on average twice a week, so plenty of practical experience/results.
...
If your hygiene is up to scratch, then rehydrating will definately give you a more viable yeast, but I have really found it unecessary.

But you're pitching Ross-sized yeast packs, right? Many brewers are pitching regular packets. If a standard pack is completely healthy, then sure, you won't need to rehydrate, but how often does the average Joe get a 100% cell count?

Ray Daniel's, "Designing Great Beers" has a great chapter on yeast. He took cell counts of various dry yeasts from various sources, and found that very few had the recommended pitch count. Most barely had the minimum viable cell count. I don't have the book with me, so can't quote the actual figures (anyone have it with them?)

My yeast supplier keeps the packs refrigerated (these are the standard Fermentis ones). I refrigerate them as soon as I get them home. I really notice a difference in lag time with and without rehydration. The science really does back it up, too: Dry pitching will affect your yeast count. Unless you have a healthy cell count, you're going to affect the fermentation.

The moral of the story is: Buy your yeast from Ross .

 

[SJW]

The moral of the story is: Buy your yeast from Ross .

Gee Mark, I hope none of our retailers on this site take offence. No offence Ross. <_<

 

[Jye]

But you're pitching Ross-sized yeast packs, right? Many brewers are pitching regular packets.

There is only 0.5 gm difference between craftbrewer and safale yeast packets, not really enough to make a difference. But I do prefer craftbrewer yeast since I know how it is packaged/stored and not just in a purged satchel.

For all you dry pitchers try and see it from the yeast perspective... you have just committed mass slaughter of billions of yeast, the guys who survived are going to be pissed and take it out on your beer

 

[///]

Have not read thru the old thread but from what i have been taught....

Dried yeast is in suspension due to process. At the end of the stage to culture the yeast is hit with O2, to halt the saturisation of the fatty acid layer.

The fatty acid layer forms to be the protective 'coat' to the cell until the yeast is thrown into wort again. At the end of a normal ferment the layer reforms and allows the yeast to sit dormant.

On a new ferment, the fatty acid layer must be dessaturated to enable the yeast to take in O2 and sugars, releasing CO2, Alcohol and other by products.

The theory behind the kick-start to desaturisation is osmotic pressure triggers the dessaturisation process. This does not apply to dried yeast, as the O2 prohibits the ressaturisation of the fatty acid layer.

This partly explains the shorter lag time for the start of fermentation by dried yeasts. I am wondering, if the rehydration in water is partly suggested on the lower osmotic pressure of straight water, effectively allowing the yeast to stretch before the race as an athlete would.

Osmotic pressure can be damaging to yeast, perhaps the 'stretch' ensures the cells are better placed to win the race than they would be by direct pitching???

Maybe... maybe???

Scotty

 

[chovain]

There is only 0.5 gm difference between craftbrewer and safale yeast packets, not really enough to make a difference. But I do prefer craftbrewer yeast since I know how it is packaged/stored and not just in a purged satchel.

Oh - I thought people were pitching the full 24g . (Have never used Ross' yeast myself)

 

[pint of lager]

Thanks Scotty for that very detailed post, I knew the rehydration bit was due to osmotic pressure, but not some of the other bits.

Do you have any ideas about the higher temperature? We all try and not shock our yeast by dramatic temperature changes, but the standard hydration notes say 35 deg C.

 

[ohitsbrad]

We all try and not shock our yeast by dramatic temperature changes, but the standard hydration notes say 35 deg C.

Yes and that is really my point. Rehydrating or not is one issue. But the temperature you rehydrate the yeast at (and pitch at) is another.

If you do rehydrate, then Palmer (and I'm sure other texts) recommends doing so at 35 to 40 deg, with no real explanation why. You would then pitch into say 20 deg wort. Would this shock the yeast? And to what extent? Maybe it's negligible.

Over the page Palmer goes on to discuss the importance of making starters with liquid yeast at the same temperature you plan to ferment your beer at, to avoid shocking the yeast. Why is this definitely an issue for making starters with liquid yeast and not for rehydrating dried yeast.

 

[Jye]

If you do rehydrate, then Palmer (and I'm sure other texts) recommends doing so at 35 to 40 deg, with no real explanation why. You would then pitch into say 20 deg wort. Would this shock the yeast? And to what extent? Maybe it's negligible.

From the Danstar site.

Step 2.

* After 15 minutes stir until all yeast is suspended

* Leave undisturbed for another 5 minutes.

* Adjust temperature of solution to that of the wort in 10C (18F) steps, by adding small amounts
of wort at 5 minutes intervals and mixing gently (ATTEMPERATION)

From this Im assuming there is some shock but minimal if you are dropping to temp in 10C steps.

 

[PistolPatch]

PP, it is time to read the most recent thread on note taking. No more blaming the yeast for poor results when you have used the same sample for umpteen brews.

Yep POL, that's the main reason I started that thread on note-taking. (I think you forgot a smiley there - lol!) I was absolutely sure that new sachets of yeast were pitched in the funky brews that harry_rambler and I did but it wasn't until tonight, that I had a chance with Harry to back-track our two dodgy brews. They were not new sachets of yeast. They were actually my yeast cake harvests thank God!

My understanding of yeast cake harvesting was as you mentioned a few posts ago...

They also suggest not using slurry beyond 6-7 generations/brews as the risk of infection and mutation is too high.

You certainly can't get umpteen generations out of slurry but you can get quite a few.

I probably got around ten generations out of my yeast slurry without perfect practices. In hindsight, following the procedure I wrote above about smelling and tasting the water from the slurry (a practice taught to me by countless others on AHB) would have prevented those dodgy brews. Harry has only a few AG's under his belt and I forgot to remind him to smell and taste the slurry I dropped off to him. I smelled and tasted the same slurry water a few days later before I was about to pitch and immediately, just upon smelling, knew that the yeast had gone off.

Anyway ten generations wasn't bad!

Spot ya,
Pat

 

[dr K]

Scotty the triple slasher mentions the fatty acid condom around yeast cells, this is a very common protective mechanism, and is exactly the reason why something as simple as washing our hands with soap is one of the most effective ways to stop the spread of all sorts of disease, the soap and the friction emulsify the fatty acid layer making death by , I guess you could say drowning, inevitable.
I use liquid yeast, I generally make my first batch 20 litres and all tings being well do another 2 x 40 litre batches...100 litres for $15 is good value, low risk.

K

 

[PistolPatch]

Palmer suggests rehydrating dry yeast in a cup of water at 35 to 40 degrees, and pitching after half an hour. Lets say the yeast solution cools further to around 30 degrees in that half hour. Is there no issue with shocking or stunning the yeast when you pitch it to a cooler wort, say 20 degrees, like there is if you had've made and pitched a liquid yeast starter at warmer temperatures than the wort?

No one else is going to say it but Palmer's advice above, if quoted accurately, at best it is risky and certainly not detailed enough to make it correct. It may have some merit though I seriously doubt it. I have never ever seen anyone suggesting dealing with yeast at 40 degrees????

I truly doubt that Palmer would suggest a temp anywere near 40 degrees.

Has anyone checked this quote?

Even if it is right, we have heard several testimonies from experienced brewers to just sprinkle your dried yeast on top of your wort.

So what if lag time is reduced by an hour! (If that actually! I've done all methods and have never noticed a diff, A day is a day!)

Threads like this actually annoy me. There should be a whole separate forum for people who want to discuss, ''advanced but possibly and probably wrong AG''

I know the guys who have won top medals on this forum. They simply have good recipes. One of the mash paddle winners of a huge comp does not rack his beers, He prefers the yeast to do it's work.

Threads like this confuse new brewers I reckon. If Palmer's quote at the beginning of this post is accurate then what hope does any new brewer have?

In hindsight, my advice would be to a new brewer...

1. Don't brew kits.
2. Brew Fresh Wort Kits
3. Well, I haven't thought of that yet!

This thread,was started by ohitsbrad. He's a new brewer. He's read Palmer (one of the worst references I would give any newbee - heaps simpler ones out there) and he has posed a good question.

All I know for sure is that most of the advice offered in this thread does not help him.

There is so much more simple stuff that will benefit ohitsbrad but not one person here so far has asked what level he is at. The stuff offered here so far doesn't even benefit me and I reckon I've been brewing a tad longer than ohits!

Interesting and LOL,
Pat

P.S. Have had a good read through the above. Pretty sure it is all correct.

 

[Stuster]

No one else is going to say it but Palmer's advice above, if quoted accurately, at best it is risky and certainly not detailed enough to make it correct. It may have some merit though I seriously doubt it. I have never ever seen anyone suggesting dealing with yeast at 40 degrees????

I truly doubt that Palmer would suggest a temp anywere near 40 degrees.

Has anyone checked this quote?

From here.

Re-hydrating Dry Yeast
1. Put 1 cup of warm (95-105F, 35-40C) boiled water into a sanitized jar and stir in the yeast. Cover with Saran Wrap and wait 15 minutes.
2. "Proof" the yeast by adding one teaspoon of extract or sugar that has been boiled in a small amount of water. Allow the sugar solution to cool before adding it to the jar.
3. Cover and place in a warm area out of direct sunlight.
4. After 30 minutes or so the yeast should be visibly churning and/or foaming, and is ready to pitch.

I am another sprinkler. The last time I re-hydrated some dry yeast according to instructions to the letter it died on me. So I sprinkled another packet on and away it went. Completely anecdotal of course, but I'm with an earlier poster (warren?). If I wanted to stuff around, I'd get some liquid yeast. If it's dry, then it better be easy.