Dry yeast less tolerant of temperature swings/heating?

[manticle]

Is that the one where someone shat in the kettle......
Mark

Think that one had twelve tasters.
Double the fun

 

[indica86]

I have not had any issue with MJs Saison strain.
I use that one on the bench in summer. Air temp fluctuates between 35° and 20°c.

 

[Adr_0]

I have not had any issue with MJs Saison strain.
I use that one on the bench in summer. Air temp fluctuates between 35° and 20°c.

I've done the same with other saison yeasts and would have done so with this one, but suspect I cooked it too hard. Definitely keen to give it another go as it was tasting amazing up to the last few days of fermentation.

 

[Adr_0]

See one person says dry yeasts are more robust, while others say they need to be rehydrated very carefully.

I'm also curious about vitality and given they've typically been grown under conditions with adequate O2 this should be solid - but that's only been reported by Fermentis. Do other manufacturers state the same thing? MJ's mention oxygenation in their product sheet:
"After pitching Mangrove Jack’s Beer Yeast to your wort, you will experience a lag period which varies from strain to strain, and from beer to beer; 12-24 hours is normal. The lag phase will also be impacted by the degree of oxygenation of your wort and by temperature"
vs Fermentis:
"Does the wort need Oxygenation/ aeration?
As the yeast is grown aerobically, the yeast is less sensitive on first pitch. Aeration is recommended to ensure full mixing of the wort and yeast."

I'm also very curious if there are differences in cell counts with MJ yeasts, and even yeast to yeast. While datasheets all point to >5 or 6bn cells per gram, Brewer's friend cites the following:
Yeast B cells/g
Safale__ K-97__14
Safale__ S-04___8
Safbrew_T-58__18
Safbrew_S-33__16
Saflager_S-23__10
Saflager_S-189__9

The reference I found on Homebrewtalk is pretty shallow, so I won't quote it here. Suffice to say that MJ's also report >5/6bn per gram.

I'll keep digging, and also need to try M44 packs mixed into wort and kicked off at 18°C or so, then rising into the 20/21 range.

I'd like to improve my dry yeast practice though. I'm almost there with liquids but I would say I have a way to go with dry yeasts and would like to get on top of them as my excellent LHBS stocks a good range.

 

[MHB]

MJ report more than (>) 5*10^9 cells/g so in the 10g pack 5*10^10, Wyeast and White labs both claim to have 1*10^11, about twice as much, but they cost twice as much so - meh much of a muchness on cost.
What really concerned me was the temperature wandering back and forward around the 15oC range. For most Ale yeast there is somewhere between 14-16oC a minimum temperature, under which it goes dormant. by not having good control of temperature the yeast is "switching" on and off, it preforms about as well as you or I would if someone kept waking us up every 2 hours - a day or two of that and we would be knackered!
If you get a decent population of viable yeast and let it do its thing you will get decent beer.

Using the recommended pitching rate for Ale yeast (0.4-1*10^6 cells/mL/point of Plato) 10g in 23L of 1.050 wort
(0.4*10^6)*23,000*12.5 = 115,000,000,000 or 1.15*10^11. About half the recommended minimum pitch.

Yeast needs Oxygen to reproduce, so clearly there is going to be a benefit to aerating your wort, along with everything else than needs doing properly, temp control, wort nutrients...
Mark

 

[Adr_0]

MJ report more than (>) 5*10^9 cells/g so in the 10g pack 5*10^10, Wyeast and White labs both claim to have 1*10^11, about twice as much, but they cost twice as much so - meh much of a muchness on cost.
What really concerned me was the temperature wandering back and forward around the 15oC range. For most Ale yeast there is somewhere between 14-16oC a minimum temperature, under which it goes dormant. by not having good control of temperature the yeast is "switching" on and off, it preforms about as well as you or I would if someone kept waking us up every 2 hours - a day or two of that and we would be knackered!
If you get a decent population of viable yeast and let it do its thing you will get decent beer.

Using the recommended pitching rate for Ale yeast (0.4-1*10^6 cells/mL/point of Plato) 10g in 23L of 1.050 wort
(0.4*10^6)*23,000*12.5 = 115,000,000,000 or 1.15*10^11. About half the recommended minimum pitch.

Yeast needs Oxygen to reproduce, so clearly there is going to be a benefit to aerating your wort, along with everything else than needs doing properly, temp control, wort nutrients...
Mark

If we're talking minimum pitch, to be honest I'm not that far above it:
(0.4*10^6)*23,000*10° = 92 x 10^9 and given two packs were added that's 100x10^9

So yes, I'll try again at higher/stable temperature, but looking at those numbers I'm thinking I need to be doing a bit of growth and some oxygenation.

I think people take what Fermentis says seriously - essentially that their dry yeast doesn't need oxygenation on the first pitch [if pitched in the correct viable cell quantity]. So is this another one of those things where what's written on the box doesn't reflect best practice? Sounds to me like starters with dry yeast are the go.

 

[MHB]

Agreed in part, when they harvest yeast for drying its is crash chilled/centrifuges/filtered... when its at its peak sterol content, not what we as home brewers do.
Commercially harvested dry yeast will go through a full life cycle without additional Oxygen, not saying there aren't advantages to wort aeration, just not as many as with liquid cultures and especially home cropped yeast.
Taint brewing fun.
Mark

 

[Adr_0]

Agreed in part, when they harvest yeast for drying its is crash chilled/centrifuges/filtered... when its at its peak sterol content, not what we as home brewers do.
Commercially harvested dry yeast will go through a full life cycle without additional Oxygen, not saying there aren't advantages to wort aeration, just not as many as with liquid cultures and especially home cropped yeast.
Taint brewing fun.
Mark

I just realised as well that the "0.4" in your calculations could even potentially be 0.5 or 0.7/0.8 and should be higher again for lagers.

I always love improving, so this is great to know for dry yeasts and I can make some easy changes that should result in some good improvements.

 

[Lionman]

Agreed in part, when they harvest yeast for drying its is crash chilled/centrifuges/filtered... when its at its peak sterol content, not what we as home brewers do.
Commercially harvested dry yeast will go through a full life cycle without additional Oxygen, not saying there aren't advantages to wort aeration, just not as many as with liquid cultures and especially home cropped yeast.
Taint brewing fun.
Mark

What sort of time does it take for the yeast to go through a generation? Should o2 addition be delayed with using dry yeast? A day after pitch?

 

[MHB]

No, we then go back to the yeast changing what it's doing, in this case switching back and forward between its reproductive, aerobic fermentation and anaerobic alcohol producing stages, the switching back and forward will "stress" the yeast, consuming vital nutrients and reducing the vitality of the whole population.
If you want to understand yeast, the first rule is that yeast wants to make yeast not beer.
Don't confuse the yeast, if you are going to pitch a lower than optimum population expect the ferment to take longer and to produce more side-issues (which adds its own complexities), be prepared to rack the beer to get off old/dead/stressed yeast, if you want to avoid the problems that can arise from too long a contact between old/stressed yeast and beer, golden rule is 14 days max contact with primary yeast.
Or pitch an adequate population of healthy yeast into a well aerated wort and let it do its thing.
Mark

 

[Adr_0]

I'm pretty sure I know the answer to this question, but I'll ask anyway.

I've just (deliberately) grabbed a single pack of dry yeast for a beer next week. Although it technically undoes some of the convenience, there are no issues with building up cell count in a starter are there? Should I also rehydrate before throwing into the starter wort?

 

[MHB]

What sort of time does it take for the yeast to go through a generation? Should o2 addition be delayed with using dry yeast? A day after pitch?

Under 'Ideal" conditions as little as 90 minutes, probably about 120 in a well aerated wort.
If you have a look at the instructions on the Saf website

REHYDRATION INSTRUCTIONS: Sprinkle the yeast in minimum 10 times its weight of sterile water or wort at 25 to 29°C (77°F to 84°F).
Leave to rest 15 to 30 minutes.
Gently stir for 30 minutes, and pitch the resultant cream into the fermentation vessel.
Alternatively, pitch the yeast directly in the fermentation vessel providing the temperature of the wort is above 20°C (68°F). Progressively sprinkle the dry yeast into the wort ensuring the yeast covers all the surface of wort available in order to avoid clumps. Leave for 30 minutes, then mix the wort using aeration or by wort addition.

Probably pretty good procedure, gives the yeast time to hydrate and attemperate, then hit it with O2 to give it a real kick in the right direction.
Mark

 

[bradsbrew]

Under 'Ideal" conditions as little as 90 minutes, probably about 120 in a well aerated wort.
If you have a look at the instructions on the Saf website

REHYDRATION INSTRUCTIONS: Sprinkle the yeast in minimum 10 times its weight of sterile water or wort at 25 to 29°C (77°F to 84°F).
Leave to rest 15 to 30 minutes.
Gently stir for 30 minutes, and pitch the resultant cream into the fermentation vessel.
Alternatively, pitch the yeast directly in the fermentation vessel providing the temperature of the wort is above 20°C (68°F). Progressively sprinkle the dry yeast into the wort ensuring the yeast covers all the surface of wort available in order to avoid clumps. Leave for 30 minutes, then mix the wort using aeration or by wort addition.

Probably pretty good procedure, gives the yeast time to hydrate and attemperate, then hit it with O2 to give it a real kick in the right direction.
Mark

Rehydrating yeast for 30 minutes prior to adding to wort negates the need to let sit for 30 minutes after sprinkling?

 

[MHB]

Perhaps, tho every time yeast is moved to a new environment it has to adjust (attemperate) the adjustments take time and energy that all detract from what the yeast has stored to do the job of reproducing/brewing that we have planed.
I suspect it wouldn't make a major difference to the yeasts population or vigor, but its all cumulative the best process is I suspect the simplest.
Mark

 

[Lyrebird_Cycles]

What sort of time does it take for the yeast to go through a generation?

Under ideal conditions S cerevisiae doubling time is about 90 minutes. You won't achieve this in wort, more typical doubling times in the exponential phase in wort are 3 - 4 hours.

 

[Bribie G]

No, we then go back to the yeast changing what it's doing, in this case switching back and forward between its reproductive, aerobic fermentation and anaerobic alcohol producing stages, the switching back and forward will "stress" the yeast, consuming vital nutrients and reducing the vitality of the whole population.
If you want to understand yeast, the first rule is that yeast wants to make yeast not beer.
Don't confuse the yeast, if you are going to pitch a lower than optimum population expect the ferment to take longer and to produce more side-issues (which adds its own complexities), be prepared to rack the beer to get off old/dead/stressed yeast, if you want to avoid the problems that can arise from too long a contact between old/stressed yeast and beer, golden rule is 14 days max contact with primary yeast.
Or pitch an adequate population of healthy yeast into a well aerated wort and let it do its thing.
Mark

The old time UK brewers knew what they were doing and collected their yeast for repitching either from top cropping of yeast that rose to the surface, from the "barm deck" of a Yorkshire Stone Square, or from the troughs in Burton Union systems where it had likewise been expelled from the beer and was sitting there in a more or less pure state.

Not (as we home brewers tend to do) from the sludge at the bottom of the fermenter when they got round to cleaning it out.

 

[Adr_0]

So this is rather anectodal, but after my previous experience I decided to do another beer (1.056, 16.2L requiring ~224bn cells) with 2 x packs of M44 and put it through a couple of growth starters and a vitality starter (1L, 1.8L, 500mL). So I likely had absolute shitloads more yeast vs the first one, but the setpoint was also raised 2°C just to get the true purity of the anecdote.

So no real surprises here, but after looking back through the first brew I had bumped up the temperature to 18, 19 then 20 and swirled quite a bit at the 23% attenuation mark. I would have thought that if there was adequate yeast the attenuation would have dropped fairly rapidly but it did not. I thought gravity/volume triggered yeast multiplication but I guess it's also sensitive to pitching temperature to the tune of <2°C?

The instructions on the M44 pack say "Sprinkle contents on up to 23L of fresh wort" so I'm going to call ******** on that. I'm fine to do starters - now that I know I have to - but I think that statement is drawing a pretty long bow.

Has anyone done cell counts on it that anybody knows of?

 

[Lyrebird_Cycles]

I thought gravity/volume triggered yeast multiplication but I guess it's also sensitive to pitching temperature to the tune of <2°C?

Has anyone done cell counts on it that anybody knows of?

Typical dry yeast has a cell count around 10^10 cells per gram so an 11 g pack is around 10^11 cells.

The triggers to yeast muliplication are more complex than is generally appreciated: a yeast cell that is about to bud will send out a signal compound, if there are enough other cells doing the same thing the concentration of the compound will rise to a level that triggers growth. The minimal cell count for this to occur is about 10^6 cells /ml. IIRC the stimulus for the signal compound is uptake of an appropriate carbon source (eg sugar) and the onset of mitosis.

 

[Adr_0]

It's a curiosity but it's basically not the core issue with that particular beer. I suspect that the growth enzymes are firing at the start and if starting conditions (including cell count and temperature) aren't right then more cells won't be there later in the fermentation. I am still mildly curious why a required range of (0.5 to 1) x 20,000 x 10°C = 100-200bn cells required and supposedly 200bn cells pitched (at 10 x 10^9/gram x 20g) didn't finish stronger.

I'm just going to have to err on the cautious side, build up dry yeasts and just go with it.

And get a microscope. And haemocytometer. And some micro pippettes. And some beer.

 

[Adr_0]

Typical dry yeast has a cell count around 10^10 cells per gram so an 11 g pack is around 10^11 cells.

The triggers to yeast muliplication are more complex than is generally appreciated: a yeast cell that is about to bud will send out a signal compound, if there are enough other cells doing the same thing the concentration of the compound will rise to a level that triggers growth. The minimal cell count for this to occur is about 10^6 cells /ml. IIRC the stimulus for the signal compound is uptake of an appropriate carbon source (eg sugar) and the onset of mitosis.

I have to ask... Have you done any yeast cell counting before? I presume you have access to the equipment and you certainly have the expertise.