[Steve Ruch]

I hope that everyone who took the White Labs tour noticed the big orbital shaker table in the propagation lab.  I did not see a single stir plate in use at White Labs.

I'll stop using mine as soon as I get a big orbital shaker table!  In the meanwhile, I've proven to myself that a stir plate works better and faster than any other method I've tried.

So, get a stir plate?

[narvin]

Actually, a shaker table is the preferred laboratory device for propagating yeast.  What shaking does is aerate the culture in a low stress way.  Spinning the stir bar fast enough to aerate a culture on a stir plate can place significant shear stress on the cells, resulting in an unhealthy culture. That's why many stirred cultures smell foul.

Mine smells delightful, thank you very much 

[narvin]

In my humble opinion, modern home brewing yeast pitching dogma is doing more harm than good.  My discussions with the brewers at White Labs only confirmed this belief.

After trying their beers at the tasting room, I'm not sure I trust their palate on brewing advice.  They know how to grow yeast, but I don't think they've figured out the optimal fermentation parameters for making any of the beer styles they had on tap last week.

I'm not going to make a beer with 5% DME... period.  Canned wort is even worse, since the malt oxidation is so extreme by the time I pop the top that it smells like honey.

Given that I don't have time to shake a starter more than once at the beginning, using a stir plate creates more yeast slurry than not using one, every time.  This makes it easier to get to my desired pitch rate for a given beer style.  I decant and pitch the slurry from the bottom, just like every commercial brewery that doesn't top crop.  The yeast is viable after staining.  The beer is happy.  The times I've been disappointed, actually, are when I start directly with a White Labs pitch 

[S. cerevisiae]

Given that I don't have time to shake a starter more than once at the beginning, using a stir plate creates more yeast slurry than not using one, every time.  This makes it easier to get to my desired pitch rate for a given beer style.

 

A stir plate does not allow one to exceed maximum cell density.  A stir plate does not provide much in the way of aeration when run at a speed low enough to prevent shear stress.  Any increase in yeast biomass is the result of cells that have kicked the bucket.  Continuous propagation overcomes the maximum cell density problem by continuously removing yeast cells.

I decant and pitch the slurry from the bottom, just like every commercial brewery that doesn't top crop.

However, that's not how breweries perform an initial pitch.  Breweries that do not own a propagator usually start by inoculating an initial amount of wort at a rate of 1L of purchased yeast per barrel.  This initial inoculation is stepped at a rate of 10 to 1 when the propagation media reaches approximately 50% attenuation. 

  The yeast is viable after staining.  The beer is happy. 

Please post microscope photo a methylene blue stained slide of your yeast. 

The times I've been disappointed, actually, are when I start directly with a White Labs pitch

No one is suggesting that one should perform a direct pitch.  One of the critical things that a starter does when using White Labs yeast is allow the yeast cells to wake up and reverse the survival-related morphological changes that they underwent at the end of batch fermentation at White Labs in a relatively low density, high yeast cell to wort volume environment.  This step is critical because the remaining viable cells have usually had time to consume a good percentage of their glycogen stores. 

[S. cerevisiae]

So, get a stir plate?

You do not need waste money on a stir plate.  Do yourself a favor search the forum using the terms "shaken, not stirred" and "James Bond Method."  You probably already own everything that you need to make a healthy starter using this method.

[narvin]

Given that I don't have time to shake a starter more than once at the beginning, using a stir plate creates more yeast slurry than not using one, every time.  This makes it easier to get to my desired pitch rate for a given beer style.

 

A stir plate does not allow one to exceed maximum cell density.  A stir plate does not provide much in the way of aeration when run at a speed low enough to prevent shear stress.  Any increase in yeast biomass is the result of cells that have kicked the bucket.  Continuous propagation overcomes the maximum cell density problem by continuously removing yeast cells.

 

Agreed, but a stir plate does help reach maximum cell density for a large starter (3-4L) in my experience, which is very helpful when making 10 gallons of lager or high gravity ale.

  The yeast is viable after staining.  The beer is happy. 

Please post microscope photo a methylene blue stained slide of your yeast. 

I'll do that after my next starter, as long as I can get my cell phone camera to cooperate with my student microscope's eyepiece.

[denny]

I hope that everyone who took the White Labs tour noticed the big orbital shaker table in the propagation lab.  I did not see a single stir plate in use at White Labs.

I'll stop using mine as soon as I get a big orbital shaker table!  In the meanwhile, I've proven to myself that a stir plate works better and faster than any other method I've tried.

So, get a stir plate?

Got one and use it every time I make a starter.

[denny]

So, get a stir plate?

You do not need waste money on a stir plate.  Do yourself a favor search the forum using the terms "shaken, not stirred" and "James Bond Method."  You probably already own everything that you need to make a healthy starter using this method.

Fortunately, one was given to me, so no money wast wasted.  And I still can't reconcile my personal results with your "best practices".  My own experience is that using a stir plate and decanting produces better beer at my house than shaking the starter and pitching at high krausen.  I respect the science, but I must be in some sort of Bermuda Triangle of non-science since it doesn't work like that for me.

[mchrispen]

I am actually working on a blog article looking at this. A friend spent the big bucks on an orbital shaker table some time ago. I have a stir plate. Planning to pressure cook wort and the stir plate, shaker table and shake method and do some viability and counting, fermentation with split batch wort. I may try to weave in a dry v rehydrated version as well... but with very rough manufacturer cell estimates in dry yeast, not sure it would be valid.

In the "Selecting Yeast Based on Strain.... yada longest seminar name ever" Kevin Lane said their pitching rates were based on biomass (dry weight) and not cell counts, advice that follows closely with Mark's recommendations. They are also adjusting their viability recommendations quite a bit. I was pretty surprised frankly... it's a large shift from the White Labs and Wyeast advice, but it was also seemed to be inferred that WL was propagating to mass in their new process and that the cell counts were significantly increased in their new process/packaging.

I was surprised in Kevin's advice on pitching dry and not rehydrated, but apparently they don't see in their labs the significant yeast die off from pitching into wort that others have reported. I "seem" to get better results with rehydration, but willing to admit personal bias. I spoke with him briefly after - he said the difference was really in lag times and not in ester/phenol expression. It was a bit boggling as I have done side by side tests with meads (1.100 gravity must) and the results were very different between 71B-1122 dry pitch and rehydration with GoFerm (as recommended by Schramm and Pietz), with the sugar break feedings.

[S. cerevisiae]

I am actually working on a blog article looking at this. A friend spent the big bucks on an orbital shaker table some time ago. I have a stir plate. Planning to pressure cook wort and the stir plate, shaker table and shake method and do some viability and counting, fermentation with split batch wort. I may try to weave in a dry v rehydrated version as well... but with very rough manufacturer cell estimates in dry yeast, not sure it would be valid.

I was reading a paper on shaker tables last night.  One thing I found interesting was that the author claimed that the media volume should be no larger than 25% of the flask volume in order for the technique to be most effective.  This publication parallels my finding with well-shaken starters.  In the case of the shaker table, a media volume of 25% or less of the flask volume increases the surface area that is exposed to air.  My rationale for having at least that much extra volume is that it allows for expansion during shaking. Media (wort in this case), when expanded to foam, has significantly more surface area than media in pure liquid form.  I wonder how much more effective a stir plate spun at a slow enough speed to prevent shear stress would be if the media volume was limited to 10% of the flask volume.  Given two flasks of the same size with the same amount of media, the flask placed on the shaker table would have a larger amount of surface area than the flask placed on a stir plate due to the shaker table's orbital pattern causing the media to slosh up on to the sides of the flask.

[majorvices]

I have never noticed any negative effects from shearing when making starters on a stir plate and feel comfortable recommending that as a propagation technique.

I like the comment made by Narvin about "After trying their beers at the tasting room, I'm not sure I trust their palate on brewing advice." Similar experience on my end. Yeast biologists grow great yeast, and maltsters malt great malt and hop growers grow great hops but when I have tasted their beers I have not usually been very impressed. Leave the brewing to the brewers.

[toby]

I thought the point of the beers in the tasting room was to compare what different yeast strains do to the same base beer.  In that vein, the 'standard' yeast should be a good beer (which applied to the two flights I tasted), and then anything 'off' in the others is going to be the result of the interplay of the style with that yeast strain.  I get the impression they don't try to get complimentary flavors as much as highlight what the yeast does.  Some of those wind up making an interesting and different good beer, and some wind up being a train wreck.

[narvin]

I thought the point of the beers in the tasting room was to compare what different yeast strains do to the same base beer.  In that vein, the 'standard' yeast should be a good beer (which applied to the two flights I tasted), and then anything 'off' in the others is going to be the result of the interplay of the style with that yeast strain.  I get the impression they don't try to get complimentary flavors as much as highlight what the yeast does.  Some of those wind up making an interesting and different good beer, and some wind up being a train wreck.

Yes, but I didn't love the' standard' beer of any style.  The closest was the hefe with 300, but it still wasn't my favorite.

[mabrungard]

Keith, I haven't found detriment to my stirred starters since I typically stir slowly and use a 3" stir bar. But I don't doubt that a shaken vessel could be better than stirred. My point is that this appears to be a case of 'good and better'. Stir plates are still good and should be used, if you have one. Most of us won't have the opportunity to move up to a shaker like White Labs has.

[toby]

Yes, but I didn't love the' standard' beer of any style.  The closest was the hefe with 300, but it still wasn't my favorite.

I wouldn't expect to love any of their beers though.  I would just expect them to be middle of the road examples (something I would score in the mid-30s in a comp for example).  Their goal isn't to make beers I love.  It's to propagate and sell yeast.  They only have a tasting room to highlight what the yeast can do.