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General Category => Yeast and Fermentation => Topic started by: JohnnyC on June 14, 2018, 11:44:03 AM

Title: Vindication for us non-rehydrators
Post by: JohnnyC on June 14, 2018, 11:44:03 AM
https://fermentis.com/news-from-fermentis/technical-reviews/e2u-direct-pitching/ (https://fermentis.com/news-from-fermentis/technical-reviews/e2u-direct-pitching/)
Title: Re: Vindication for us non-rehydrators
Post by: TANSTAAFB on June 14, 2018, 01:18:56 PM
I appreciate the scientific support, especially directly from the manufacturer. But those of us who direct pitch have known this for years! It is interesting that they now recommend mixing the wort and yeast rather than the sprinkle on top and let it slowly rehydrate method.

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Title: Re: Vindication for us non-rehydrators
Post by: JohnnyC on June 14, 2018, 01:47:11 PM
I appreciate the scientific support, especially directly from the manufacturer. But those of us who direct pitch have known this for years! It is interesting that they now recommend mixing the wort and yeast rather than the sprinkle on top and let it slowly rehydrate method.

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I thought that was interesting, too. Had actually thought about tyring that. Now I will.
Title: Re: Vindication for us non-rehydrators
Post by: Iliff Ave Brewhouse on June 14, 2018, 03:19:12 PM
By coincidence that's how I've always done it. It's funny that wort and and yeast want to make beer. It doesn't have to be complicated which is great for me...
Title: Re: Vindication for us non-rehydrators
Post by: ynotbrusum on June 14, 2018, 03:47:03 PM
I have tried it all three ways that he describes, as well as adding O2 and sprinkling on top without mixing in - with the same conclusion.  For what it is worth, I wonder how the lager yeasts track at fermentation temperatures...it will be interesting to see the full report that he alludes to be forthcoming.
Title: Re: Vindication for us non-rehydrators
Post by: Robert on June 14, 2018, 06:04:55 PM
Good timing.  I've rarely used dry yeast,  but just decided under summer time constraints to grab some S-04 and direct pitch.  Now I'm encouraged.  Interestingly, their technical data sheet suggests an alternate method:  sprinkle on top of wort in the fermenter, leave 30 minutes, then aerate to mix.  Maybe I'll add the aeration step.  Or not.

It's funny that wort and and yeast want to make beer. It doesn't have to be complicated which is great for me...
:D
Title: Re: Vindication for us non-rehydrators
Post by: seefish on June 15, 2018, 03:30:05 AM
https://fermentis.com/news-from-fermentis/technical-reviews/e2u-direct-pitching/ (https://fermentis.com/news-from-fermentis/technical-reviews/e2u-direct-pitching/)

Not sure how they could say there was no difference...the DP clearly lagged behind early on and ended up with more volatile compounds.  Dunno if that would make a difference in flavor but I kinda think it would...
Title: Re: Vindication for us non-rehydrators
Post by: Todd H. on June 15, 2018, 03:13:47 PM
https://fermentis.com/news-from-fermentis/technical-reviews/e2u-direct-pitching/ (https://fermentis.com/news-from-fermentis/technical-reviews/e2u-direct-pitching/)

Not sure how they could say there was no difference...the DP clearly lagged behind early on and ended up with more volatile compounds.  Dunno if that would make a difference in flavor but I kinda think it would...

The data points make it look like it lagged up to day 2, but I bet if you ran stats on that, there is no difference between groups (I do these kind of analyses all the time at work).  They all finished the same, so even if DP lagged a little for two days, does it matter?
Also, the volatile compounds graphs look identical to me when you take error into account (and were not statistically significant according to the author).

When I use dry yeast, I mostly rehydrate.  Think I'll skip that and eliminate one possible source of contamination.  I've never noticed direct pitching to be detrimental when I have done it.
Title: Re: Vindication for us non-rehydrators
Post by: hopfenundmalz on June 15, 2018, 03:17:01 PM
Some of the smaller breweries around here will fill the conical cone, open the manway and sprinkle the dry yeast in, close the manway, then pump the rest of the wort in.
Title: Re: Vindication for us non-rehydrators
Post by: Robert on June 16, 2018, 01:12:53 AM
Did the DP today, S-04, calculated my pitch rate based on the 8B cells/g for this strain given in the study cited by Brewer's Friend.  Used the method given in the TDS:  Sprinkled on the wort at 73°F, left it for 30 min, and aerated (air, not 02 for this) to mix.  Moved to fermentation chamber set to hold ambient at 60°F.   Came back to check after 5 1/2 hours, and it's at 68°F in the thermowell (target fermentation temp) and active.  Will see how it tracks from here.  For ales, I may never use liquid yeast again.  Or bother repitching.  Not sure how this could be adapted for lager fermentation.  If I have to rehydrate and attemperate adding aliquots of wort, it'd be just as easy to use liquid yeast and make a starter.  But at this point, I may have had one of those life-changing events...so simple!  :)
Title: Re: Vindication for us non-rehydrators
Post by: TANSTAAFB on June 16, 2018, 01:47:54 AM
I've direct pitched with 34/70 (warm fermented no less, gasp) and had great results.

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Title: Re: Vindication for us non-rehydrators
Post by: denny on June 16, 2018, 02:48:12 PM
I've direct pitched with 34/70 (warm fermented no less, gasp) and had great results.

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Same here, and I'm going to do it again today.
Title: Re: Vindication for us non-rehydrators
Post by: TANSTAAFB on June 16, 2018, 03:20:32 PM
I've direct pitched with 34/70 (warm fermented no less, gasp) and had great results.

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Same here, and I'm going to do it again today.
Whatcha making?

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Title: Re: Vindication for us non-rehydrators
Post by: cmb4642 on June 16, 2018, 04:37:33 PM
When I started brewing I used dry yeast rehydrated and was convinced my beers would be better using liquid culture with starters and the whole nine yards. My beers got better over time but so to did my process and recipes. I find my schedule more erratic the last year and was tossing liquid cultures because brewday wasn’t working. I now keep several packs of dry yeast around and there isn’t much we can’t brew with dry. In terms of rehydration with fairly straightforward OG worts, I gave up on that also. I believe this offers another source of contamination and even if viability is reduce, the dead yeast serve as free yeast nutrients for the little beasties that survive. Great article. Thanks for the post.


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Title: Re: Vindication for us non-rehydrators
Post by: denny on June 16, 2018, 04:56:31 PM
I've direct pitched with 34/70 (warm fermented no less, gasp) and had great results.

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Same here, and I'm going to do it again today.
Whatcha making?

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German pils
Title: Re: Vindication for us non-rehydrators
Post by: BrewBama on June 16, 2018, 06:52:17 PM
I’ve never heard of anyone keeping liquid yeast as an emergency backup for dry yeast. Dry always works for me and I’ve been very happy with it for a long time now. I haven’t used liquid yeast in fornever.  Never had a fail even well past the expiration date. I can’t say that about liquid.


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Title: Re: Vindication for us non-rehydrators
Post by: cmb4642 on June 16, 2018, 07:57:18 PM
I’ve never heard of anyone keeping liquid yeast as an emergency backup for dry yeast. Dry always works for me and I’ve been very happy with it for a long time now. I haven’t used liquid yeast in fornever.  Never had a fail even well past the expiration date. I can’t say that about liquid.


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Wasn’t for emergency, it was what I planned to brew with. Brew days kept getting pushed back and then culture was well beyond expiration so I switched back to dry.


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Title: Re: Vindication for us non-rehydrators
Post by: Robert on June 16, 2018, 08:12:17 PM
I've direct pitched with 34/70 (warm fermented no less, gasp) and had great results.

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Same here, and I'm going to do it again today.
Whatcha making?

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German pils
This I gotta try.  When you guys say "warm," what do you mean?  64°-68°F-ish?
Title: Re: Vindication for us non-rehydrators
Post by: BrewBama on June 16, 2018, 08:49:29 PM
I’ve never heard of anyone keeping liquid yeast as an emergency backup for dry yeast. Dry always works for me and I’ve been very happy with it for a long time now. I haven’t used liquid yeast in fornever.  Never had a fail even well past the expiration date. I can’t say that about liquid.


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Wasn’t for emergency, it was what I planned to brew with. Brew days kept getting pushed back and then culture was well beyond expiration so I switched back to dry.


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Oh ...I wasn’t directing my comments your way. I was simply making a statement about why I’ve been using dry vs liquid yeast. I apologize for any confusion. Cheers!


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Title: Re: Vindication for us non-rehydrators
Post by: denny on June 16, 2018, 09:14:51 PM
I've direct pitched with 34/70 (warm fermented no less, gasp) and had great results.

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Same here, and I'm going to do it again today.
Whatcha making?

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German pils
This I gotta try.  When you guys say "warm," what do you mean?  64°-68°F-ish?

I still ferment lagers in the mid 50s...old habits die hard.   But I've fermented a pils with 34/70 at 65 to try it and as far as I could tell it was indistinguishable from the ones done at 55. No blind triangle so I won't sweat to that.  I also use 34/70 as my go to dry ale yeast and ferment it at 63-65.  I far prefer it to US05.
Title: Re: Vindication for us non-rehydrators
Post by: TANSTAAFB on June 16, 2018, 09:19:07 PM
I've fermented a Helles lager at 68-70°F and it was delicious!

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Title: Re: Vindication for us non-rehydrators
Post by: a10t2 on June 16, 2018, 09:39:58 PM
It would be interesting to see the results for strains that are known (or at least believed) to have more flavor variation due to pitching rates.
Title: Re: Vindication for us non-rehydrators
Post by: Robert on June 16, 2018, 09:43:52 PM
I've fermented a Helles lager at 68-70°F and it was delicious!

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Cool, thanks guys.  In the summer my IC even with prechiller can't get me to lager temp, takes several hours in the fridge to get all the way down.  Sounds like I can pitch 34/70 at room temperature,  and move it into the fermentation chamber, and not really worry how cool I set it.   Rediscovering dry yeast has me kind of giddy.  Takes the hassle out of brewing and puts the emphasis back on fun, creativity, spontaneity.
Title: Re: Vindication for us non-rehydrators
Post by: Robert on June 16, 2018, 09:45:53 PM
It would be interesting to see the results for strains that are known (or at least believed) to have more flavor variation due to pitching rates.
How are you thinking that would differ between liquid and dry versions?
Title: Re: Vindication for us non-rehydrators
Post by: Steve Ruch on June 16, 2018, 09:58:58 PM
I've fermented a Helles lager at 68-70°F and it was delicious!

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Cool, thanks guys.  In the summer my IC even with prechiller can't get me to lager temp, takes several hours in the fridge to get all the way down.  Sounds like I can pitch 34/70 at room temperature,  and move it into the fermentation chamber, and not really worry how cool I set it.   Rediscovering dry yeast has me kind of giddy.  Takes the hassle out of brewing and puts the emphasis back on fun, creativity, spontaneity.
I've pitched 34/70 in the mid 60s and put it into my fermenting chamber at 52 many times. It gets down to the low 50s overnight and I see signs of fermentation shortly thereafter.
Title: Re: Vindication for us non-rehydrators
Post by: a10t2 on June 16, 2018, 09:59:15 PM
How are you thinking that would differ between liquid and dry versions?

I'm wondering if the reducing pitching rate from rehydrating in wort would be more apparent in something less neutral than US-05, not that it would necessarily be any different from a liquid form of the same strain given the same pitching rate.
Title: Re: Vindication for us non-rehydrators
Post by: Robert on June 16, 2018, 10:21:05 PM
How are you thinking that would differ between liquid and dry versions?

I'm wondering if the reducing pitching rate from rehydrating in wort would be more apparent in something less neutral than US-05, not that it would necessarily be any different from a liquid form of the same strain given the same pitching rate.
I think on the periphery of this topic is another question (your assumption?) that has to be answered first: does direct pitching in wort really kill some of the yeast, or is that outdated information?  For that matter, does rehydrating first damage yeast?  The article in the OP's link suggests direct pitching does no damage, we'll have to wait for the full report.
Title: Re: Vindication for us non-rehydrators
Post by: TANSTAAFB on June 16, 2018, 10:54:56 PM
I've fermented a Helles lager at 68-70°F and it was delicious!

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Cool, thanks guys.  In the summer my IC even with prechiller can't get me to lager temp, takes several hours in the fridge to get all the way down.  Sounds like I can pitch 34/70 at room temperature,  and move it into the fermentation chamber, and not really worry how cool I set it.   Rediscovering dry yeast has me kind of giddy.  Takes the hassle out of brewing and puts the emphasis back on fun, creativity, spontaneity.
Until I recently acquired a chest freezer, all my fermentation control crapped out during a move. No clue why but both my fridges worked when I unplugged them and loaded them on the uhaul and didn't work when I plugged them back in. But my basement stays in the mid to high 60's and I started following both the warm fermented lager thread on HBT and the stuff Brulosophy has done so I just fermented at ambient temps. No problems, lager or ale. FWIW, I think DNA testing has shown that 34/70 is actually an ale strain that performs well at lower temps which explains why it does fine at higher temps as well.

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Title: Re: Vindication for us non-rehydrators
Post by: riceral on June 17, 2018, 01:06:51 AM
I've fermented a Helles lager at 68-70°F and it was delicious!

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Cool, thanks guys.  In the summer my IC even with prechiller can't get me to lager temp, takes several hours in the fridge to get all the way down.  Sounds like I can pitch 34/70 at room temperature,  and move it into the fermentation chamber, and not really worry how cool I set it.   Rediscovering dry yeast has me kind of giddy.  Takes the hassle out of brewing and puts the emphasis back on fun, creativity, spontaneity.
Until I recently acquired a chest freezer, all my fermentation control crapped out during a move. No clue why but both my fridges worked when I unplugged them and loaded them on the uhaul and didn't work when I plugged them back in.

OK, I know this might sound off the wall, but----

Maybe it's the outlet that isn't working.

Just a thought.
Title: Re: Vindication for us non-rehydrators
Post by: ynotbrusum on June 17, 2018, 01:27:07 AM
I have had success with pitching S-189@ 62F and slowlly moving  it down to 149F.  I can’t get it down to my normal 58 F pitching temp and I would like to be lower on my starting temp, but it has worked great to start high and drop to ferment temps over night...
Title: Re: Vindication for us non-rehydrators
Post by: TANSTAAFB on June 17, 2018, 01:29:05 AM
I've fermented a Helles lager at 68-70°F and it was delicious!

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Cool, thanks guys.  In the summer my IC even with prechiller can't get me to lager temp, takes several hours in the fridge to get all the way down.  Sounds like I can pitch 34/70 at room temperature,  and move it into the fermentation chamber, and not really worry how cool I set it.   Rediscovering dry yeast has me kind of giddy.  Takes the hassle out of brewing and puts the emphasis back on fun, creativity, spontaneity.
Until I recently acquired a chest freezer, all my fermentation control crapped out during a move. No clue why but both my fridges worked when I unplugged them and loaded them on the uhaul and didn't work when I plugged them back in.

OK, I know this might sound off the wall, but----

Maybe it's the outlet that isn't working.

Just a thought.
Nope, both old fridges just gave it up! All good though, got a Best Buy special Insignia kegerator that I upgraded with an Intertap tower and picked up a chest freezer cheap at a yard sale that is now my fermentation chamber controlled by an STC 1000 build.

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Title: Re: Vindication for us non-rehydrators
Post by: Robert on June 17, 2018, 01:52:28 AM
I have had success with pitching S-189@ 62F and slowlly moving  it down to 149F.  I can’t get it down to my normal 58 F pitching temp and I would like to be lower on my starting temp, but it has worked great to start high and drop to ferment temps over night...

Sounds like I have a new SOP, direct pitch above 68°F as the manufacturer recommends, then let it drop to (whatever) temperature overnight.  Funny how you get stuck on the conventional wisdom that flavor will be impaired if you pitch warm and then cool.  Then again, it was conventional wisdom that you can't direct pitch, or that dry yeast is inferior.  I should have been tipped off by all the commercial brewers around here using dry yeast and direct pitching. BTW my ferment dropped to 64°F overnight even as activity shot up, has since climbed to 66°, and now at 30 hours the bubbling in the jar of Star San is not bubbling at all, it's a buzz, sounds like a little 2-stroke model airplane engine in my fridge.  I'm guessing that direct pitching does not kill or weaken yeast.  ;)
Title: Re: Vindication for us non-rehydrators
Post by: ynotbrusum on June 17, 2018, 12:31:03 PM
Yep, mine is buzzing along now in the low 50’s this morning.  I know a guy who is Siebel trained and he has won awards with his lagers over the years - it is his process exactly in terms of temperature.  Start in the 60’s and lower it while it is getting active down into the 50’s.  Of course, taste will be the real test.  Here’s hoping it tastes great.

Cheers!
Title: Re: Vindication for us non-rehydrators
Post by: Robert on June 17, 2018, 03:01:05 PM
Well, 43 hours after pitching, and the S-04 has ripped mine down from 13°P to 4°P!  They said it's fast. Direct pitching works for me.  Dry hopped and set ambient to 70°F.
Title: Vindication for us non-rehydrators
Post by: BrewBama on June 17, 2018, 03:52:50 PM
Until I recently acquired a chest freezer, all my fermentation control crapped out during a move. No clue why but both my fridges worked when I unplugged them and loaded them on the uhaul and didn't work when I plugged them back in...

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Give the fridges a bit to settle the Freon out. They may very well work if just left for a few daze. Especially if jostled around during the move.


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Title: Re: Vindication for us non-rehydrators
Post by: jeffy on June 17, 2018, 04:41:39 PM
Until I recently acquired a chest freezer, all my fermentation control crapped out during a move. No clue why but both my fridges worked when I unplugged them and loaded them on the uhaul and didn't work when I plugged them back in...

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Give the fridges a bit to settle the Freon out. They may very well work if just left for a few daze. Especially if jostled around during the move.


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This is good advice, but it isn’t the refrigerant that settles, it’s the oil in the system, particularly in the compressor.  If you had to lay the unit on its side, the oil needs some time to settle back to the bottom or else it may damage the compressor.
Title: Re: Vindication for us non-rehydrators
Post by: a10t2 on June 17, 2018, 05:08:40 PM
I think on the periphery of this topic is another question (your assumption?) that has to be answered first: does direct pitching in wort really kill some of the yeast, or is that outdated information?  For that matter, does rehydrating first damage yeast?

Sure, data can always be contradicted or invalidated, but we don't typically used the word "assumption" to refer to the results of repeated hypothesis and controlled experiment. That's a "theory".

The article in the OP's link suggests direct pitching does no damage, we'll have to wait for the full report.

I just re-read it to make sure, and there's no mention of either potential or observed viability effects.

The most interesting thing I noticed was the comparatively enormous error bars for the "W" trials - without any discussion of methods it's hard to infer much from that other than that the results from the rehydrated samples were remarkably inconsistent. A large variation in ethanol content without a corresponding variation in ADF at least suggests contamination to me, and if that trial was also the one exhibiting outlier levels of VDKs and acetaldehyde that's a smoking gun IMHO.
Title: Re: Vindication for us non-rehydrators
Post by: BrewBama on June 17, 2018, 05:56:26 PM
Until I recently acquired a chest freezer, all my fermentation control crapped out during a move. No clue why but both my fridges worked when I unplugged them and loaded them on the uhaul and didn't work when I plugged them back in...

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Give the fridges a bit to settle the Freon out. They may very well work if just left for a few daze. Especially if jostled around during the move.


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This is good advice, but it isn’t the refrigerant that settles, it’s the oil in the system, particularly in the compressor.  If you had to lay the unit on its side, the oil needs some time to settle back to the bottom or else it may damage the compressor.

+1. I knew SOMETHING had to settle. LOL


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Title: Re: Vindication for us non-rehydrators
Post by: Robert on June 18, 2018, 09:56:57 PM
Reading through the Fermentis website again, I see the no-need-to-rehydrate advice applies only to the yeasts labelled "E2U" easy to use, which is most but not all of their brewing products.  They are specially prepared with a protective emulsion which prevents damage and loss of viable cells during rehydration in wort, it seems; hence there is no difference in effective pitch rate between various methods including DP.  So in effect, there should be no pitch rate-related differences in performance or flavor -- at least with these yeasts.  Presumably rehydration in water is still advisable for other yeasts and other manufacturers' products, and the familiar, necessary assumptions about losses in direct pitching still apply there. (I hadn't noticed this was a supposedly new thing until I realized not all their strains are labelled E2U.)
Title: Re: Vindication for us non-rehydrators
Post by: denny on June 18, 2018, 10:45:00 PM
Reading through the Fermentis website again, I see the no-need-to-rehydrate advice applies only to the yeasts labelled "E2U" easy to use, which is most but not all of their brewing products.  They are specially prepared with a protective emulsion which prevents damage and loss of viable cells during rehydration in wort, it seems; hence there is no difference in effective pitch rate between various methods including DP.  So in effect, there should be no pitch rate-related differences in performance or flavor -- at least with these yeasts.  Presumably rehydration in water is still advisable for other yeasts and other manufacturers' products, and the familiar, necessary assumptions about losses in direct pitching still apply there. (I hadn't noticed this was a supposedly new thing until I realized not all their strains are labelled E2U.)

A friend who worked for them for many years maintains that neither hydration nor aeration is necessary.  I believe him.
Title: Re: Vindication for us non-rehydrators
Post by: Robert on June 18, 2018, 10:58:06 PM
Master Brewers podcast #93: Active Dry Yeast (http://masterbrewerspodcast.com/093-active-dry-yeast) may be of interest.
+1
Title: Re: Vindication for us non-rehydrators
Post by: a10t2 on June 19, 2018, 12:29:55 AM
Master Brewers podcast #93: Active Dry Yeast (http://masterbrewerspodcast.com/093-active-dry-yeast) may be of interest.

Interesting stuff; for those curious the relevant statement starts at about 19:30 in the podcast.

I'm really interested to hear more about the E2U products. I can't say that I'm on top of the state of the art in dried yeast but this seems to be the first mention of a fundamentally new process.

Edit: OK, maybe I'm going all Costner in JFK here, but I can't find anything online about E2U. Actually, I can't find a single official reference to it as anything other than "the E2U direct pitching procedure". Always the complete phrase. Basically, I don't doubt this is a new procedure, I'm just trying to find some evidence it's a new product.
Title: Re: Vindication for us non-rehydrators
Post by: Robert on June 19, 2018, 01:37:35 AM
Master Brewers podcast #93: Active Dry Yeast (http://masterbrewerspodcast.com/093-active-dry-yeast) may be of interest.

Interesting stuff; for those curious the relevant statement starts at about 19:30 in the podcast.

I'm really interested to hear more about the E2U products. I can't say that I'm on top of the state of the art in dried yeast but this seems to be the first mention of a fundamentally new process.

Edit: OK, maybe I'm going all Costner in JFK here, but I can't find anything online about E2U. Actually, I can't find a single official reference to it as anything other than "the E2U direct pitching procedure". Always the complete phrase. Basically, I don't doubt this is a new procedure, I'm just trying to find some evidence it's a new product.
Early in the page the OP linked it says:  "To permit a good resistance to rehydration, the yeast is coated with a protective agent (most times the vegetal emulsifier sorbitan monostearate (MSS)) just prior to drying."  The article and podcast both refer to the yeasts they tested (E2U) showing no loss of viability or vitality in DP.  They don't, I grant you, seem to offer a direct comparison to anyone else's product and I don't know if others use similar processes.  I expect more info to come, Fermentis  seem to be on tour with this, as it were.  But heck, why not just try a DP yourself and see how it goes?  I understand you want data, but we drink beer, not numbers. What works, works.
Title: Re: Vindication for us non-rehydrators
Post by: a10t2 on June 19, 2018, 01:39:16 AM
But heck, why not just try a DP yourself and see how it goes?

Fair enough; I'll pick up a couple packs and do some new counts.
Title: Re: Vindication for us non-rehydrators
Post by: Robert on June 19, 2018, 01:48:56 AM
But heck, why not just try a DP yourself and see how it goes?

Fair enough; I'll pick up a couple packs and do some new counts.
I know you'll report back.  But if you're doing a side-by-side, tracking fermentation and sensory analysis will be interesting.  It's just possible the counts are a red herring.  (I'm thinking of the arguments pertaining to vitality starters.)
EDIT  and full disclosure, I've never tried the vitality method, always been a conventional, pitch-rate obsessed brewer.  But I keep finding myself surprised these days.
Title: Re: Vindication for us non-rehydrators
Post by: a10t2 on June 19, 2018, 02:18:33 AM
But if you're doing a side-by-side, tracking fermentation and sensory analysis will be interesting.  It's just possible the counts are a red herring.  (I'm thinking of the arguments pertaining to vitality starters.)
EDIT  and full disclosure, I've never tried the vitality method, always been a conventional, pitch-rate obsessed brewer.  But I keep finding myself surprised these days.

I'll try to get a decent sized triangle test together as well; the problem is I'm adjacent to the middle of nowhere and I know my own palate is wrong often enough that I won't trust it for that kind of thing.

And I can definitely relate to rethinking the pitching rate obsession; I massively under pitched a batch recently and while there are definite differences it's far from undrinkable (have a pint in hand now, in fact).
Title: Re: Vindication for us non-rehydrators
Post by: Robert on June 20, 2018, 11:17:04 PM
Further reading on Fermentis website (Q&A):

•They say that direct pitching  presents the potential for a maximum loss of viable cells of 3-6%.

•They also say that while the labelling/TDS gives a count of ">6B" viable cells/g, at packaging there are 10B viable cells/g.

Very helpful for determining a pitch rate. (Looks like I guessed my way into hitting it just about right anyway this time.)
Title: Re: Vindication for us non-rehydrators
Post by: Saccharomyces on July 29, 2018, 12:44:45 PM
Interestingly, their technical data sheet suggests an alternate method:  sprinkle on top of wort in the fermenter, leave 30 minutes, then aerate to mix.  Maybe I'll add the aeration step.  Or not.

In reality, unless one is seriously underpitching, wort does not need to be aerated when using dry yeast.  Dry yeast is grown under aerobic conditions below the Crabtree threshold in a bioreactor.  It is a very efficient way to propagate yeast cells because yeast cells produce more energy from the medium using the aerobic metabolic pathway instead of the anaerobic metabolic pathway.  The bonus is that the cells come out of the bioreactor with fully charged ergosterol and unsaturated fatty acids reserves.  The reason why we aerate wort is to provide O2 for the synthesization of these compounds during the lag phase.
Title: Re: Vindication for us non-rehydrators
Post by: BrewBama on July 29, 2018, 01:15:49 PM
Interestingly, their technical data sheet suggests an alternate method:  sprinkle on top of wort in the fermenter, leave 30 minutes, then aerate to mix.  Maybe I'll add the aeration step.  Or not.

In reality, unless one is seriously underpitching, wort does not need to be aerated when using dry yeast.  Dry yeast is grown under aerobic conditions below the Crabtree threshold in a bioreactor.  It is a very efficient way to propagate yeast cells because yeast cells produce more energy from the medium using the aerobic metabolic pathway instead of the anaerobic metabolic pathway.  The bonus is that the cells come out of the bioreactor with fully charged ergosterol and unsaturated fatty acids reserves.  The reason why we aerate wort is to provide O2 for the synthesization of these compounds during the lag phase.

...and this is why we missed you. Cheers!


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Title: Re: Vindication for us non-rehydrators
Post by: Robert on July 29, 2018, 03:19:03 PM
Update:  I figured out their suggestion of aeration was just a way of introducing agitation to mix in a commercial size fermenter.  The alternative given is to fill the cone, wait 30 minutes, and fill the remainder.  I did the aeration mixing method once, and on homebrew scale it is a useless (as Sacch. explains) complication.  Rocking my Speidel does the trick.