105 replies to this topic

[neddles]

For me the age of my packet or vial seems to be the largest determinant of how long it will take my starter to finsh. I typically use Kai's estimates but your unlikely to harm a thing using the increased quantity of Jamil's estimates.

[SchwanzBrewer]

Hmm, well for all the scientific whiz-bangery with Jamil, Kai, etc., that seems like a pretty wide range of yeast growth predictions. According to Jamil I would be 63 billion cells short and according to Kai I would have 8 billion more than I need. It's nothing I would lose sleep over but it's the type of thing that would make my 4-year-old brain wonder.

 

 

I think Kai's is more accurate - or maybe that's just wishful thinking

 

either way I've had good results using his estimates when making starters.

a little reading for when you have a minute:  https://braukaiser.c...g-yeast-growth/

 

Jamils was made with data from Jamil and Chis White (white labs). Kai did his own tests and collected his own data. Chances are the variation is due to variation in conditions and yeast stains. Again, this variation is why I don't sweat it when I don't exactly get to the number that the calc says I should be at. +/-10% is fine. Hell altitude could effect the outcome of an experiment since there's less O2 at higher altitudes, so the dissoved O2 in the wort will be less (unless they use pure O2).

 

The only way to verify what kind of growth you are getting is to get a microscope and a hemocytometer and count cells from a sample of your starter. I'm heading in that direction soon. Just because I find it interesting and I'll be able to help club members by checking for contamination and such if they bring me a sample.

 

I should add that I use Kai's equations. That guy is an inspiration.

Edited by SchwanzBrewer, 03 March 2015 - 09:45 AM.

[denny]

When you make your starter wort... what is the gravity... or how much DME should I use per liter of wort. Is that the right way to ask that question?

 

.75 oz. DME per cup of water will get you right around 1.035

DME 1.040: 1# DME to 1 gallon - approximately

 

more like 1.045

[positiveContact]

Jamils was made with data from Jamil and Chis White (white labs). Kai did his own tests and collected his own data.

 

That link I posted alluded to this but it seems like Jamil's numbers for a stir plate are not from real test results.  From the link:

 

Jamil’s pitching rate calculator supports stirred starter fermentation but the growth curve used for that mode is a simple scaling of the growth curve for non agitated starters.

 

In other words it sounds like he used good test results for a non-agitated starter and tried to just scale up the results for a stirred starter.  I guess this doesn't work that great according to Kai.

[Big Nake]

Okay so based on all of this information that I have digested and the idea that just ONE starter can be used to get to where you want, I'm going to make a 2L starter in the next day or so with 7 ounces (or so) of DME, boil it, chill it, give it a shot of pure O2 and then pitch this Activator of 2002 Gambrinus that has a date of Jan 13 2015 and then get it on the stirplate. My plan is to brew Friday evening or Saturday afternoon. When the starter appears to be winding down I will chill it, eventually decant the wort and pitch it. Thanks for the direction people.

[positiveContact]

Okay so based on all of this information that I have digested and the idea that just ONE starter can be used to get to where you want, I'm going to make a 2L starter in the next day or so with 7 ounces (or so) of DME, boil it, chill it, give it a shot of pure O2 and then pitch this Activator of 2002 Gambrinus that has a date of Jan 13 2015 and then get it on the stirplate. My plan is to brew Friday evening or Saturday afternoon. When the starter appears to be winding down I will chill it, eventually decant the wort and pitch it. Thanks for the direction people.

 

that sounds like a good plan to me!

[SchwanzBrewer]

Okay so based on all of this information that I have digested and the idea that just ONE starter can be used to get to where you want, I'm going to make a 2L starter in the next day or so with 7 ounces (or so) of DME, boil it, chill it, give it a shot of pure O2 and then pitch this Activator of 2002 Gambrinus that has a date of Jan 13 2015 and then get it on the stirplate. My plan is to brew Friday evening or Saturday afternoon. When the starter appears to be winding down I will chill it, eventually decant the wort and pitch it. Thanks for the direction people.

 

Sounds like a plan.

 

Cheers!

[brewman]

How many cups would 7oz be?

 

Dan

[denny]

How many cups would 7oz be?

 

Dan

 

Kinda hard to say.  I've seen the same volume of different brands of DME have different weights.

[matt6150]

A question I have always assumed to be correct but for a sanity check I have will ask anyway. Does everyone leave the sirplate spinning during the entire duration of it fermenting out till done?

[brewman]

I leave it running till Im ready to put it in the fridge.

[Big Nake]

A question I have always assumed to be correct but for a sanity check I have will ask anyway. Does everyone leave the sirplate spinning during the entire duration of it fermenting out till done?

I leave it spinning until it's done at which point I put it into the fridge which is probably for an hour or two before I am ready to decant it and pitch it. Once it's gotten very active and then dies back down again, I assume it's time to take it off the stirplate. Good idea to bounce this around though.

[neddles]

A question I have always assumed to be correct but for a sanity check I have will ask anyway. Does everyone leave the sirplate spinning during the entire duration of it fermenting out till done?

Yes, I do.

[denny]

A question I have always assumed to be correct but for a sanity check I have will ask anyway. Does everyone leave the sirplate spinning during the entire duration of it fermenting out till done?

 

yeah, but that's about 24-36 hours for me

[brewman]

Oh but I do take the stir bar out before I put it in the fridge.

 

Dan

[HVB]

Oh but I do take the stir bar out before I put it in the fridge.Dan

Why?

[brewman]

So i dont pour it into the wort, forget its there and dump the trub and lose it.

 

Dan

[SchwanzBrewer]

So i dont pour it into the wort, forget its there and dump the trub and lose it.

 

Dan

 

I've never dumped one into the wort. BUT there's a simple solution to that. Magnetism! just get a small magnet and couple it and the stir bar will stay put no matter what.

[HVB]

I've never dumped one into the wort. BUT there's a simple solution to that. Magnetism! just get a small magnet and couple it and the stir bar will stay put no matter what.

This is what I do as well.

[positiveContact]

I leave it running till Im ready to put it in the fridge.

 

this.

 

I've never dumped one into the wort. BUT there's a simple solution to that. Magnetism! just get a small magnet and couple it and the stir bar will stay put no matter what.

 

and this.