After racking off the heavy lees, I pitched D-254 into my sauvignon
blanc. The yeast has been in refrigeration for a year. I pitched it
Saturday night and have yet to see any fermentation activity as of this
morning. It was unseasonably cold the last 2 nights and the juice was
left out with a paper towel stuffed in the opening.

I put in ~2 tsp. for the 4 gallons of juice.

Suggestions? I would think that the juice would start fermenting in
about a day?

TIA,
Joe

Joe Giller wrote:
> After racking off the heavy lees, I pitched D-254 into my sauvignon
> blanc. The yeast has been in refrigeration for a year. I pitched it
> Saturday night and have yet to see any fermentation activity as of this
> morning. It was unseasonably cold the last 2 nights and the juice was
> left out with a paper towel stuffed in the opening.
> I put in ~2 tsp. for the 4 gallons of juice.
>
> Suggestions? I would think that the juice would start fermenting in
> about a day?
>
> TIA,
> Joe

Some thoughts:

- Did you add sodium metabisulfite to kill off native yeasts prior the
pitching the yeast? If so, how much and when? High free sulfur in the
must will inhibit yeast growth.
- At the time of pitching, having the yeast near the same temperature as
the must minimizes thermal shock (which can kill a lot of the yeast
population).
-Did you add any DAP (Diammonium Phosphate) or balanced yeast food
(Fermaid K) to the must prior to pitching the yeast? (they provide a
favorable environment for the yeast to grow)
- Year-old yeast may or may not still be viable. Before you pitched
your yeast, did u check for yeast viability? (i.e take a little bit and
put it in in warm water(around 100 deg F) with a dash of yeast nutrient
and checking for the FIZZ?
- your must may be too cold for the yeast to be active yet. What
temperature is it now?


Good luck.
Gene

Joe Giller wrote:
> After racking off the heavy lees, I pitched D-254 into my sauvignon
> blanc. The yeast has been in refrigeration for a year. I pitched it
> Saturday night and have yet to see any fermentation activity as of this
> morning. It was unseasonably cold the last 2 nights and the juice was
> left out with a paper towel stuffed in the opening.
> I put in ~2 tsp. for the 4 gallons of juice.
>
> Suggestions? I would think that the juice would start fermenting in
> about a day?
>
> TIA,
> Joe

Some thoughts:

- Did you add sodium metabisulfite to kill off native yeasts prior the
pitching the yeast? If so, how much and when? High free sulfur in the
must will inhibit yeast growth.
- At the time of pitching, having the yeast near the same temperature as
the must minimizes thermal shock (which can kill a lot of the yeast
population).
-Did you add any DAP (Diammonium Phosphate) or balanced yeast food
(Fermaid K) to the must prior to pitching the yeast? (they provide a
favorable environment for the yeast to grow)
- Year-old yeast may or may not still be viable. Before you pitched
your yeast, did u check for yeast viability? (i.e take a little bit and
put it in in warm water(around 100 deg F) with a dash of yeast nutrient
and checking for the FIZZ?
- your must may be too cold for the yeast to be active yet. What
temperature is it now?


Good luck.
Gene

Gene,
Thanks and here are the answers (or most of them)
I added 1 tsp K-metabisulfite to the grapes at crush

The juice was cool and the yeast mixture was warmer at the time I threw
it in. Could be a problem.

I added superfood (1 tbsp) with the yeast.

I will test the yeast viability tonight.

Not sure what the temp is right now, but I would say it is probably
somewhere around 55-60 degrees. (Total guess).

Thanks,
Joe

Gene,
Thanks and here are the answers (or most of them)
I added 1 tsp K-metabisulfite to the grapes at crush

The juice was cool and the yeast mixture was warmer at the time I threw
it in. Could be a problem.

I added superfood (1 tbsp) with the yeast.

I will test the yeast viability tonight.

Not sure what the temp is right now, but I would say it is probably
somewhere around 55-60 degrees. (Total guess).

Thanks,
Joe

Gene,
Thanks and here are the answers (or most of them)
I added 1 tsp K-metabisulfite to the grapes at crush

The juice was cool and the yeast mixture was warmer at the time I threw
it in. Could be a problem.

I added superfood (1 tbsp) with the yeast.

I will test the yeast viability tonight.

Not sure what the temp is right now, but I would say it is probably
somewhere around 55-60 degrees. (Total guess).

Thanks,
Joe

Gene,
Thanks and here are the answers (or most of them)
I added 1 tsp K-metabisulfite to the grapes at crush

The juice was cool and the yeast mixture was warmer at the time I threw
it in. Could be a problem.

I added superfood (1 tbsp) with the yeast.

I will test the yeast viability tonight.

Not sure what the temp is right now, but I would say it is probably
somewhere around 55-60 degrees. (Total guess).

Thanks,
Joe

Joe Giller wrote:

> Gene,
> Thanks and here are the answers (or most of them)
> I added 1 tsp K-metabisulfite to the grapes at crush
>
> The juice was cool and the yeast mixture was warmer at the time I threw
> it in. Could be a problem.
>
> I added superfood (1 tbsp) with the yeast.
>
> I will test the yeast viability tonight.
>
> Not sure what the temp is right now, but I would say it is probably
> somewhere around 55-60 degrees. (Total guess).
>
> Thanks,
> Joe
>
1 tsp 'fresh' K-metabisulfite per 4 gallons must yields on the order of
65-75ppm free SO2.
The pH of the must affects the consumption of the free SO2. 20ppm free
SO2 at crush is enough if your must pH is down around 3.2-3.4. If your
pH is above 3.6, then I'm guessing you'll be needing at least 40-50 ppm
free SO2 addition at crush.
(NOTE: The K-metabisulfite slowly degrades over time in the presence
of moisture into potassium sulfate, which does not release free SO2. So
if your K - metabisulfite is also a year or more old, you have less free
SO2 than u calculated.)
I hope you didn't add the K-metabisulfite just before pitching the
yeast. Typical practice is to add K-metabisulfite 1-3 days before
pitching the yeast (i.e. one to three day cold soak). I'm guessing I
have about 10-15 ppm free SO2 remaining at the time that I pitch yeast
in my sauv blanc.


Adding warm yeast mix to cold must isn't 'ideal practice', but you can
usually get away with it if your yeast is active and healthy. The
fermentation is fairly forgiving... as long as you don't kill too much
of the yeast in the addition process.
I allow my 100-110F temperature yeast mixture to cool (on its own - not
by refrigeration) to around 70-80F before adding to about 55-60F must.
I don't stir the yeast into the must (makes for quicker start of
fermenation... so that you're not diluting the initial yeast throughout
the must). I just pour my yeast mixture into the must and cover,
letting the bubbling from fermentation and the heat gradients in the
fermenter do the mixing to achieve a 'homogenous' fermentation after a
few days.

For Sauv Blanc, I let the must temperature rise naturally to about 70F
(until I hear active fermentation), then start lowering to 55-60F,
holding it there until fermentation stops.
My fermenter is a 4 gallon stainless steel pot (with inverted lid) in an
oversized ice chest. I add frozen one-pint bottles of water to the ice
chest (not into the fermenation tank) to do my slow cooling. I start
with 5-8 'ice' bottles and change them out once or twice a day,
depending on how fast the ice is melting and what temperature the must
is at. My rule of thumb is no more than 1F per hour temperature change,
and no more than 10F cumulative change per day. That minimizes the
thermal shock to the yeast.



Others have their favorite procedures... would be interested in hearing
what works for others.

Regards, Gene

Joe Giller wrote:

> Gene,
> Thanks and here are the answers (or most of them)
> I added 1 tsp K-metabisulfite to the grapes at crush
>
> The juice was cool and the yeast mixture was warmer at the time I threw
> it in. Could be a problem.
>
> I added superfood (1 tbsp) with the yeast.
>
> I will test the yeast viability tonight.
>
> Not sure what the temp is right now, but I would say it is probably
> somewhere around 55-60 degrees. (Total guess).
>
> Thanks,
> Joe
>
1 tsp 'fresh' K-metabisulfite per 4 gallons must yields on the order of
65-75ppm free SO2.
The pH of the must affects the consumption of the free SO2. 20ppm free
SO2 at crush is enough if your must pH is down around 3.2-3.4. If your
pH is above 3.6, then I'm guessing you'll be needing at least 40-50 ppm
free SO2 addition at crush.
(NOTE: The K-metabisulfite slowly degrades over time in the presence
of moisture into potassium sulfate, which does not release free SO2. So
if your K - metabisulfite is also a year or more old, you have less free
SO2 than u calculated.)
I hope you didn't add the K-metabisulfite just before pitching the
yeast. Typical practice is to add K-metabisulfite 1-3 days before
pitching the yeast (i.e. one to three day cold soak). I'm guessing I
have about 10-15 ppm free SO2 remaining at the time that I pitch yeast
in my sauv blanc.


Adding warm yeast mix to cold must isn't 'ideal practice', but you can
usually get away with it if your yeast is active and healthy. The
fermentation is fairly forgiving... as long as you don't kill too much
of the yeast in the addition process.
I allow my 100-110F temperature yeast mixture to cool (on its own - not
by refrigeration) to around 70-80F before adding to about 55-60F must.
I don't stir the yeast into the must (makes for quicker start of
fermenation... so that you're not diluting the initial yeast throughout
the must). I just pour my yeast mixture into the must and cover,
letting the bubbling from fermentation and the heat gradients in the
fermenter do the mixing to achieve a 'homogenous' fermentation after a
few days.

For Sauv Blanc, I let the must temperature rise naturally to about 70F
(until I hear active fermentation), then start lowering to 55-60F,
holding it there until fermentation stops.
My fermenter is a 4 gallon stainless steel pot (with inverted lid) in an
oversized ice chest. I add frozen one-pint bottles of water to the ice
chest (not into the fermenation tank) to do my slow cooling. I start
with 5-8 'ice' bottles and change them out once or twice a day,
depending on how fast the ice is melting and what temperature the must
is at. My rule of thumb is no more than 1F per hour temperature change,
and no more than 10F cumulative change per day. That minimizes the
thermal shock to the yeast.



Others have their favorite procedures... would be interested in hearing
what works for others.

Regards, Gene

Joe - I think you added a lot more SO2 than you thought....around 220 ppm.
The K Metabisulfite I buy from Presque Isle weighs 5.8 grams per
teaspoonful.
K Metabisulfite is 57.63% SO2 so a tsp contains 3.34 grams SO2.
Divide the 3.34 grams SO2 by 4 gallons and you end up with about 220 ppm
SO2.
This may be your problem with a slow fermentation.

Bill Frazier
Olathe, Kansas USA

"Joe Giller" > wrote in message
...
> Gene,
> Thanks and here are the answers (or most of them)
> I added 1 tsp K-metabisulfite to the grapes at crush
>
> The juice was cool and the yeast mixture was warmer at the time I threw
> it in. Could be a problem.
>
> I added superfood (1 tbsp) with the yeast.
>
> I will test the yeast viability tonight.
>
> Not sure what the temp is right now, but I would say it is probably
> somewhere around 55-60 degrees. (Total guess).
>
> Thanks,
> Joe
>

Joe - I think you added a lot more SO2 than you thought....around 220 ppm.
The K Metabisulfite I buy from Presque Isle weighs 5.8 grams per
teaspoonful.
K Metabisulfite is 57.63% SO2 so a tsp contains 3.34 grams SO2.
Divide the 3.34 grams SO2 by 4 gallons and you end up with about 220 ppm
SO2.
This may be your problem with a slow fermentation.

Bill Frazier
Olathe, Kansas USA

"Joe Giller" > wrote in message
...
> Gene,
> Thanks and here are the answers (or most of them)
> I added 1 tsp K-metabisulfite to the grapes at crush
>
> The juice was cool and the yeast mixture was warmer at the time I threw
> it in. Could be a problem.
>
> I added superfood (1 tbsp) with the yeast.
>
> I will test the yeast viability tonight.
>
> Not sure what the temp is right now, but I would say it is probably
> somewhere around 55-60 degrees. (Total guess).
>
> Thanks,
> Joe
>

William and Gene,
Thanks so much for the info. Good tips. I checked it when I got home
last night and the fermentation had started. Phew! I will be employing
your guys's tips next time though. Thanks!

Joe

William and Gene,
Thanks so much for the info. Good tips. I checked it when I got home
last night and the fermentation had started. Phew! I will be employing
your guys's tips next time though. Thanks!

Joe

William and Gene,
Thanks so much for the info. Good tips. I checked it when I got home
last night and the fermentation had started. Phew! I will be employing
your guys's tips next time though. Thanks!

Joe

Joe, Bill is right about the SO2, although Gene is right about pH
dependency. I just think Bill is closer to the SO2 load you put in
than Gene is. The normal dose for a 5-gallon carboy is 1/4 teaspoon
of K-meta, and you quadrupled that for only 4 gallons.

My advice has always been to make a yeast starter. You will know very
quickly if the yeast is viable because the yeast is confined to a
small volume of liquid. If you dump it into a 4 or 5 gallon volume,
you might waste two or three days before deciding the yeast is no
good.

Generally, when making a starter, never put yeast in water warmer than
100 degrees F. Most wine yeast die at 104 degrees, although some can
hold out to 110. Don't play with the health of your yeast. They make
the wine. You just facilitate the experience and clean up after them.
But each yeast strain is different.

You said you were using Lalvin ICV-D254. This yeast has an optimum
fermentation range of 64-82 degrees F., with a low tolerance of 53 and
a high of 89. Within those limits, it should ferment. In the
optimum range, it should ferment very well. However, it is a
low-foaming slow fermenter, which is why it delivers a rich mouthfeel.

As for temperature shock, I am fairly certain the yeast do not
experience die-off unless they exceed the limits for the strain (for
this one, as described above). Yeast that have undergone temperature
shock are usually just stunned and go into a sort of hibernation that
can last from several hours to several days. ICV-D254 is an ADY
(active dry yeast), not a freeze-dried yeast as many people think. It
becomes active when rehydrated. I don't think it can go into shock
until then (I refrigerate mine at 40 degrees F.), so if you added the
dry yeast to a cold must it should have activated if within the
temperature limits mentioned above.

I hope this helps. If I misstated anything, Lum, Tom S., Ray, Ed,
Joe, and others will correct me so stay tuned.

Jack Keller, The Winemaking Home Page
http://winemaking.jackkeller.net/

Joe, Bill is right about the SO2, although Gene is right about pH
dependency. I just think Bill is closer to the SO2 load you put in
than Gene is. The normal dose for a 5-gallon carboy is 1/4 teaspoon
of K-meta, and you quadrupled that for only 4 gallons.

My advice has always been to make a yeast starter. You will know very
quickly if the yeast is viable because the yeast is confined to a
small volume of liquid. If you dump it into a 4 or 5 gallon volume,
you might waste two or three days before deciding the yeast is no
good.

Generally, when making a starter, never put yeast in water warmer than
100 degrees F. Most wine yeast die at 104 degrees, although some can
hold out to 110. Don't play with the health of your yeast. They make
the wine. You just facilitate the experience and clean up after them.
But each yeast strain is different.

You said you were using Lalvin ICV-D254. This yeast has an optimum
fermentation range of 64-82 degrees F., with a low tolerance of 53 and
a high of 89. Within those limits, it should ferment. In the
optimum range, it should ferment very well. However, it is a
low-foaming slow fermenter, which is why it delivers a rich mouthfeel.

As for temperature shock, I am fairly certain the yeast do not
experience die-off unless they exceed the limits for the strain (for
this one, as described above). Yeast that have undergone temperature
shock are usually just stunned and go into a sort of hibernation that
can last from several hours to several days. ICV-D254 is an ADY
(active dry yeast), not a freeze-dried yeast as many people think. It
becomes active when rehydrated. I don't think it can go into shock
until then (I refrigerate mine at 40 degrees F.), so if you added the
dry yeast to a cold must it should have activated if within the
temperature limits mentioned above.

I hope this helps. If I misstated anything, Lum, Tom S., Ray, Ed,
Joe, and others will correct me so stay tuned.

Jack Keller, The Winemaking Home Page
http://winemaking.jackkeller.net/

Jack Keller wrote:
> Joe, Bill is right about the SO2, although Gene is right about pH
> dependency. I just think Bill is closer to the SO2 load you put in
> than Gene is. The normal dose for a 5-gallon carboy is 1/4 teaspoon
> of K-meta, and you quadrupled that for only 4 gallons.
>
> My advice has always been to make a yeast starter. You will know very
> quickly if the yeast is viable because the yeast is confined to a
> small volume of liquid. If you dump it into a 4 or 5 gallon volume,
> you might waste two or three days before deciding the yeast is no
> good.
>
> Generally, when making a starter, never put yeast in water warmer than
> 100 degrees F. Most wine yeast die at 104 degrees, although some can
> hold out to 110. Don't play with the health of your yeast. They make
> the wine. You just facilitate the experience and clean up after them.
> But each yeast strain is different.
>
> You said you were using Lalvin ICV-D254. This yeast has an optimum
> fermentation range of 64-82 degrees F., with a low tolerance of 53 and
> a high of 89. Within those limits, it should ferment. In the
> optimum range, it should ferment very well. However, it is a
> low-foaming slow fermenter, which is why it delivers a rich mouthfeel.
>
> As for temperature shock, I am fairly certain the yeast do not
> experience die-off unless they exceed the limits for the strain (for
> this one, as described above). Yeast that have undergone temperature
> shock are usually just stunned and go into a sort of hibernation that
> can last from several hours to several days. ICV-D254 is an ADY
> (active dry yeast), not a freeze-dried yeast as many people think. It
> becomes active when rehydrated. I don't think it can go into shock
> until then (I refrigerate mine at 40 degrees F.), so if you added the
> dry yeast to a cold must it should have activated if within the
> temperature limits mentioned above.
>
> I hope this helps. If I misstated anything, Lum, Tom S., Ray, Ed,
> Joe, and others will correct me so stay tuned.
>
> Jack Keller, The Winemaking Home Page
> http://winemaking.jackkeller.net/
Thanks for the correction, Jack. Sounds like I had faulty info on
powdered K-metabisulfite (I use Campden tablets myself due to very small
lot size).
Thanks also for the comment on yeast starter temperature. My yeast must
have been pretty healthy to activate and survive above 100F.

Gene

Jack Keller wrote:
> Joe, Bill is right about the SO2, although Gene is right about pH
> dependency. I just think Bill is closer to the SO2 load you put in
> than Gene is. The normal dose for a 5-gallon carboy is 1/4 teaspoon
> of K-meta, and you quadrupled that for only 4 gallons.
>
> My advice has always been to make a yeast starter. You will know very
> quickly if the yeast is viable because the yeast is confined to a
> small volume of liquid. If you dump it into a 4 or 5 gallon volume,
> you might waste two or three days before deciding the yeast is no
> good.
>
> Generally, when making a starter, never put yeast in water warmer than
> 100 degrees F. Most wine yeast die at 104 degrees, although some can
> hold out to 110. Don't play with the health of your yeast. They make
> the wine. You just facilitate the experience and clean up after them.
> But each yeast strain is different.
>
> You said you were using Lalvin ICV-D254. This yeast has an optimum
> fermentation range of 64-82 degrees F., with a low tolerance of 53 and
> a high of 89. Within those limits, it should ferment. In the
> optimum range, it should ferment very well. However, it is a
> low-foaming slow fermenter, which is why it delivers a rich mouthfeel.
>
> As for temperature shock, I am fairly certain the yeast do not
> experience die-off unless they exceed the limits for the strain (for
> this one, as described above). Yeast that have undergone temperature
> shock are usually just stunned and go into a sort of hibernation that
> can last from several hours to several days. ICV-D254 is an ADY
> (active dry yeast), not a freeze-dried yeast as many people think. It
> becomes active when rehydrated. I don't think it can go into shock
> until then (I refrigerate mine at 40 degrees F.), so if you added the
> dry yeast to a cold must it should have activated if within the
> temperature limits mentioned above.
>
> I hope this helps. If I misstated anything, Lum, Tom S., Ray, Ed,
> Joe, and others will correct me so stay tuned.
>
> Jack Keller, The Winemaking Home Page
> http://winemaking.jackkeller.net/
Thanks for the correction, Jack. Sounds like I had faulty info on
powdered K-metabisulfite (I use Campden tablets myself due to very small
lot size).
Thanks also for the comment on yeast starter temperature. My yeast must
have been pretty healthy to activate and survive above 100F.

Gene

(Jack Keller) wrote in message . com>...
>

> Generally, when making a starter, never put yeast in water warmer than
> 100 degrees F. Most wine yeast die at 104 degrees, although some can
> hold out to 110.

Actually, 104 degress F is the recommended temp from one of the yeast
companies.
>
>
> As for temperature shock, I am fairly certain the yeast do not
> experience die-off unless they exceed the limits for the strain (for
> this one, as described above).

Again accourding to a yeast company, you can lose as much as half the
viable cells from temp. shock. The recommendation was to add a small
amount of must to the yeast starter 15 minutes after rehydrating the
yeast in plain water. Continue to add small amounts of must every 15
minutes or so until the starter is at the temp. of the must, then
pitch.

Andy

(Jack Keller) wrote in message . com>...
>

> Generally, when making a starter, never put yeast in water warmer than
> 100 degrees F. Most wine yeast die at 104 degrees, although some can
> hold out to 110.

Actually, 104 degress F is the recommended temp from one of the yeast
companies.
>
>
> As for temperature shock, I am fairly certain the yeast do not
> experience die-off unless they exceed the limits for the strain (for
> this one, as described above).

Again accourding to a yeast company, you can lose as much as half the
viable cells from temp. shock. The recommendation was to add a small
amount of must to the yeast starter 15 minutes after rehydrating the
yeast in plain water. Continue to add small amounts of must every 15
minutes or so until the starter is at the temp. of the must, then
pitch.

Andy

Note that different yeast companies have different suggestions on how to
introduce thier yeast to your must. One will recommend that you sprinkle it
over the top and not stir it in. Another will recomend that you add the
yeast to a certain type of starter. Another will tellyou to rehydrade and
then add to a starter. I assume that each company knows the best way you
should handle their yeast according to the way they handle the yeast
themselves in preparation. I recommend that you do it the way the company
that makes the yeast suggests.

Ray

"JEP" > wrote in message
om...
> (Jack Keller) wrote in message
> . com>...
>>
>
>> Generally, when making a starter, never put yeast in water warmer than
>> 100 degrees F. Most wine yeast die at 104 degrees, although some can
>> hold out to 110.
>
> Actually, 104 degress F is the recommended temp from one of the yeast
> companies.
>>
>>
>> As for temperature shock, I am fairly certain the yeast do not
>> experience die-off unless they exceed the limits for the strain (for
>> this one, as described above).
>
> Again accourding to a yeast company, you can lose as much as half the
> viable cells from temp. shock. The recommendation was to add a small
> amount of must to the yeast starter 15 minutes after rehydrating the
> yeast in plain water. Continue to add small amounts of must every 15
> minutes or so until the starter is at the temp. of the must, then
> pitch.
>
> Andy

Note that different yeast companies have different suggestions on how to
introduce thier yeast to your must. One will recommend that you sprinkle it
over the top and not stir it in. Another will recomend that you add the
yeast to a certain type of starter. Another will tellyou to rehydrade and
then add to a starter. I assume that each company knows the best way you
should handle their yeast according to the way they handle the yeast
themselves in preparation. I recommend that you do it the way the company
that makes the yeast suggests.

Ray

"JEP" > wrote in message
om...
> (Jack Keller) wrote in message
> . com>...
>>
>
>> Generally, when making a starter, never put yeast in water warmer than
>> 100 degrees F. Most wine yeast die at 104 degrees, although some can
>> hold out to 110.
>
> Actually, 104 degress F is the recommended temp from one of the yeast
> companies.
>>
>>
>> As for temperature shock, I am fairly certain the yeast do not
>> experience die-off unless they exceed the limits for the strain (for
>> this one, as described above).
>
> Again accourding to a yeast company, you can lose as much as half the
> viable cells from temp. shock. The recommendation was to add a small
> amount of must to the yeast starter 15 minutes after rehydrating the
> yeast in plain water. Continue to add small amounts of must every 15
> minutes or so until the starter is at the temp. of the must, then
> pitch.
>
> Andy

> Actually, 104 degress F is the recommended temp from one of the yeast
> companies.

Andy, actually, you are right about that. Lallemand recommends
rehydrating at 104 degrees, but they are also the source for the
104-degree die-off temperature. Upon checking my email, I see that is
a fermentation temperature and leads to "rapid fatality." The optimum
temperatures for various stains, however, is published and for
ICV-D254 is as I have stated. Also, Lallemand's web site states,
"...try to avoid fermentation temperatures above 35°C (95°F) since
most yeast strains cannot tolerate higher temperatures...."

> Again accourding to a yeast company, you can lose as much as half the
> viable cells from temp. shock.

If you don't want to name the company here, please send me the
reference off-group. I'm always looking for varying points of view.

> The recommendation was to add a small amount of must to the yeast starter 15
> minutes after rehydrating the yeast in plain water. Continue to add small
> amounts of must every 15 minutes or so until the starter is at the temp. of
> the must, then pitch.

That is very similar to my recommended method of building a starter,
but for different reasons. My reasoning is to get the yeast
acclimated to the must so adjustment to the pure must will be rapid
and lead to rapid propagation.

Again going back to Lallemand's site, "If you decide to start below
15°C (59°F), adjust the yeast suspension temperature to prevent yeast
cold shock by slowly (over 30 to 60 seconds) mixing an equal amount of
juice to be fermented with the rehydrated yeast suspension." They say
that cold fermentation will result in "slower fermentation," which I
agree with, but don't mention the 50% die-off from cold shock you
cite. This doesn't mean they or right or the one you cite is wrong,
but it does suggest differences in opinion. Since I use more
Lallemand (Lalvin) yeasts than any other, I tend to follow Clayton
Cone's recommendations. I rarely have any problems with yeast.

Jack Keller, The Winemaking Home Page
http://winemaking.jackkeller.net/

(Jack Keller) wrote in message . com>...
>
> Andy, actually, you are right about that. Lallemand recommends
> rehydrating at 104 degrees, but they are also the source for the
> 104-degree die-off temperature. Upon checking my email, I see that is
> a fermentation temperature and leads to "rapid fatality." The optimum
> temperatures for various stains, however, is published and for
> ICV-D254 is as I have stated. Also, Lallemand's web site states,
> "...try to avoid fermentation temperatures above 35°C (95°F) since
> most yeast strains cannot tolerate higher temperatures...."

I think the difference is between rehydration(fairly short duration
and may even drop to below 100 F just by adding the yeast) and
fermentation (sustained high temp). If I was fermenting at > 100 F, I
think yeast mortality would only be one of the problems encountered.

>
> If you don't want to name the company here, please send me the
> reference off-group. I'm always looking for varying points of view.

The above is from Dr. Cone from Lallemand. I too tend to use Lallemand
yeast when ever possible.

As to the die off from the cold shock, I don't remember the source
right now. I will look for it. It may have been when the HBD hosted a
question and answer session with a yeast company (White Labs??), but
it was a few years ago. If and when I find it, I'll send it over.

I think we both agree, that reducing the temperature of the starter
quickly can lead to problems. Even if 50% of the population dies, the
yeast will ferment the must, just slower. If they just go dormant,
they will ferment the must, just slower.


Andy

Jack,

I stand corrected on the death of the yeast due to temperature shock
if the yeast is rehydrated before pitching. I found a few sources
about it killing yeast

http://www.fst.vt.edu/extension/enol...r-April99.html
http://www.homebeerwinecheese.com/REHYDRATE%20YEAST.htm
http://www.homecraft.on.ca/news/z2000feb.htm


but, I found a lot more information indicating that the cold shock
will inhibit yeast growth and induce petit mutants rather than kill
them. Perhaps I misinterpreted a statement about the difference in
viable cell counts to mean the yeast died rather than failed to
propagate.

During rehydration though:

"With rehydration water at lower temperatures the transformation from
crystalline to gel is less successful, the cell wall becomes porous
and leaches out vital parts of its insides. Rehydration in 60°F water
can result in a loss of 60% of the yeast viability.

http://consumer.lallemand.com/dansta...html#rehydrate

Andy