Change starter's OG in method C. White Shaking don't change the final result

[Brewer #343189]

Hi, I'm trying to use the starter calculator, but when we change the OG of the starter's wort using the C. White Shaking method, the final quantity of viable cells does not change. In the Stir Plate method it changes, but not in this one. Naturally the wort density is a crucial factor for the propagation of cells, and the same result appears for OG 1010 or 1090. What to do?

 

[Pricelessbrewing]

Hi, I'm trying to use the starter calculator, but when we change the OG of the starter's wort using the C. White Shaking method, the final quantity of viable cells does not change. In the Stir Plate method it changes, but not in this one. Naturally the wort density is a crucial factor for the propagation of cells, and the same result appears for OG 1010 or 1090. What to do?

Hello,

In general, changing the gravity of your starter is not recommended. A SG of 1.036-1.037 is recommended as it's the best balance between yeast vitality (nutrients), yeast viability, growth rate, and growing in a not stressed environment.

With that said, the C. White growth is taken from the published book below, and is simply based on some experimental data that relates growth rate to the inoculation rate.

White, Chris, and Jamil Zainasheff. Yeast: The Practical Guide to Beer Fermentation. Boulder, CO: Brewers Publications, 2010. 139-44. Print.

The remaining growth factors are based on an empirical study done by Chris White, which is detailed in:
White, Chris, and Jamil Zainasheff. Yeast: The Practical Guide to Beer Fermentation. Boulder, CO: Brewers Publications, 2010. 139-44. Print.
This model is based on an inoculation rate leading to a yeast growth factor. We approximated results from that study and fitted it to an equation provided below. There are some caveats to the model to be aware of.

The maximum growth factor is 6 (the starter will never grow past that amount).

The saturation point for a starter is 200 million cells/ml (the starter not grow at that inoculation rate).

The growth curve is geared for a starter gravity of 1.036 (9 ° P).

The initial study did not address stir plates or shaking methods. However, anecdotally, aeration and stirring are said to provide positive benefits. We do not have a citation for this unfortunately, but if you can point us towards one we would be happy to update this page and the calculator logic.

As such the only parameters are how big of a starter you're making, and how much yeast you're adding to the starter.

 

[Brewer #427722]

Hi, I know this thread is several years old, but the same issue exists now (the C. White Shaking option doesn't respond to changes in starter gravity). I see the explanation makes sense (this option is based on a very limited study that doesn't account for certain variables). There is another issue that I'm wondering if anyone can help with. The only options for aeration method on the calculator are Shaking, No Agitation, and Stir Plate. Do these all assume pure 02 aeration up front? I didn't think that was the case, but maybe it is. If the 'Shaking' option, for example, assumes that shaking (without 02 injection) is the only aeration method, then pure 02 up front with no agitation afterward I would think would produce much more growth than merely shaking (but not as much as continuous aeration with a stir plate).

If anyone has further info on this it would be greatly appreciated. In other words, I'm assuming that heavy pure 02 up front in the starter (with no agitation afterwards) would produce a significantly higher cell count than merely Shaking (but not as much as stir plate). If that's true it would be great to have some sense of where in between the result might fall, because there is a massive difference in cell count in the calculator between Shaking and Stir Plate. These differences are very large.

 

[Yooper]

Hi, I know this thread is several years old, but the same issue exists now (the C. White Shaking option doesn't respond to changes in starter gravity). I see the explanation makes sense (this option is based on a very limited study that doesn't account for certain variables). There is another issue that I'm wondering if anyone can help with. The only options for aeration method on the calculator are Shaking, No Agitation, and Stir Plate. Do these all assume pure 02 aeration up front? I didn't think that was the case, but maybe it is. If the 'Shaking' option, for example, assumes that shaking (without 02 injection) is the only aeration method, then pure 02 up front with no agitation afterward I would think would produce much more growth than merely shaking (but not as much as continuous aeration with a stir plate).

If anyone has further info on this it would be greatly appreciated. In other words, I'm assuming that heavy pure 02 up front in the starter (with no agitation afterwards) would produce a significantly higher cell count than merely Shaking (but not as much as stir plate). If that's true it would be great to have some sense of where in between the result might fall, because there is a massive difference in cell count in the calculator between Shaking and Stir Plate. These differences are very large.

No, it's not commonly done to put pure O2 into a starter.
Although I guess you could.

One reason a stir plate works so well is because not only is there possible o2 uptake, you're degassing the c02 out as well (and CO2 is toxic to yeast so degassing helps with yeast health)

 

[Minbari]

No, it's not commonly done to put pure O2 into a starter.
Although I guess you could.

One reason a stir plate works so well is because not only is there possible o2 uptake, you're degassing the c02 out as well (and CO2 is toxic to yeast so degassing helps with yeast health)

Be an interesting experiment to bubble pure o2 into a starter on a stir plate and see if it makes any difference.

 

[Donoroto]

It should, but I'm not aware of anyone who's ever tried it.

 

[Ozarks Mountain Brewery]

Be an interesting experiment to bubble pure o2 into a starter on a stir plate and see if it makes any difference.

You can bet white labs has tried that, they did a lot of experimentation back in the day

 

[Pricelessbrewing]

I believe the findings were that the extra o2 didn't make any significant differences in the yeast vitality or viability, and no difference at all in the cells produced. Getting rid of c02 in solution was the main positive significant variable during testing.

I can't remember where or who I got this from, could be from the yeast book, could be from chit chatting with Chris White, or Richard from Escarpment, or one of the guys at Omega Yeast Labs as there were several who were club members in a previous club.

 

[Minbari]

I believe the findings were that the extra o2 didn't make any significant differences in the yeast vitality or viability, and no difference at all in the cells produced. Getting rid of c02 in solution was the main positive significant variable during testing.

I can't remember where or who I got this from, could be from the yeast book, could be from chit chatting with Chris White, or Richard from Escarpment, or one of the guys at Omega Yeast Labs as there were several who were club members in a previous club.

Without a scientific way to measure, it will be anecdotal for sure. But gonna try this for the next few batches and see if it seems to help or not

If nothing else, the o2 will expel the co2out

 

[Brewer #427722]

It would be an interesting experiment Minbari, but the question I raised in my post is a different one (which you may already know--sorry, I'm still just curious about this). My question is also one that should be easy to measure. My question is, if someone doesn't have a stir plate available, what would the difference in final starter cell count be using pure 02 aeration of the starter wort at the outset vs only shaking? I would think that the pure 02 would be much better than simply shaking. But the yeast calculators don't have such an option listed. It's either stir plate, or just shaking. Obviously it's better just to use a stir plate in all cases if possible, but it seems like pure 02 (easy to do if you have a stone) would be a far better second option than shaking.

 

[Minbari]

It would be an interesting experiment Minbari, but the question I raised in my post is a different one (which you may already know--sorry, I'm still just curious about this). My question is also one that should be easy to measure. My question is, if someone doesn't have a stir plate available, what would the difference in final starter cell count be using pure 02 aeration of the starter wort at the outset vs only shaking? I would think that the pure 02 would be much better than simply shaking. But the yeast calculators don't have such an option listed. It's either stir plate, or just shaking. Obviously it's better just to use a stir plate in all cases if possible, but it seems like pure 02 (easy to do if you have a stone) would be a far better second option than shaking.

Hard to say without a quantitative way to measure to outcome. (Same for my experiment)

But in general, shaking or stirring alone will get you 8ppm oxygen vs 22ppm using pure o2. So yes, theoretically, pure o2 would be better

 

[Ozarks Mountain Brewery]

I know this isn’t the topic but I wanted to point out that moving the yeast around like using a stir plate is for the purpose to grow the yeast as much as possible without fermenting and without creating trub, so another good test would be to use a stir plate or not and which you will get more and purer yeast