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WoodlandBrew · 01-29-2013, 05:46 PM

You could cold crash for a month and still have enough healthy yeast. Some will get sucked from the cake when you rack to the bottling bucket. Right now I'm running a comparison test of yeast from a starter to yeast that was refrigerated for a month and the performance is indistinguishable.

dlcumpton · 01-29-2013, 06:18 PM

Quote:

Originally Posted by shanecb

I've cold crashed for over a week and still had plenty left for bottling. Even if the beer looks clear to the eye there's still a ton of yeast in suspension. But cold crashing for 2 or 3 days is typically sufficient for my beers, so would be a good starting point.

Awesome thanks for the quick reply

stewart194 · 01-29-2013, 06:42 PM

Quote:

Originally Posted by WoodlandBrew

You could cold crash for a month and still have enough healthy yeast. Some will get sucked from the cake when you rack to the bottling bucket. Right now I'm running a comparison test of yeast from a starter to yeast that was refrigerated for a month and the performance is indistinguishable.

In your comparison test, what are you doing exactly? Are you also making a starter out of the yeast that has been refrigerated or are you just dumping it in as is?

Based on a technical article on this website, I began making a starter with a fresh WYeast pack and I made it 500ml more than I needed for my beer. I put that 500ml of yeast in a sterile mason jar and put it in the fridge. I've done this for my last 3 batches and now have 1272, 1084, and 1098 on hand.

The part that I wasn't sure about, is do I now make a new starter with these 500ml jars and treat them like that are a single WYeast smack pack?

WoodlandBrew · 01-29-2013, 09:48 PM

Quote:

Originally Posted by stewart194

In your comparison test, what are you doing exactly? Are you also making a starter out of the yeast that has been refrigerated or are you just dumping it in as is?

I've been collecting daily data on two fermentations, and will be collecting starting and final data on a matrix of 40 additional fermentations. The daily data is on intermittently shaken starters with an inoculation rate of about 65 million per ml and a 9°P wort. Data is %sucrose, %alcohol, live cell and total cell counts.

The matrix is an array of 3°P to 15°P worts, and four inoculation rates for each of the two yeasts. At the termination of the test attenuation and cell count will be done.

The "inactive" yeast has been in the fridge for a month, the "active" yeast was taken from the "inactive" yeast three days before setting up the culture tubes. It was started in a 9°P wort and shaken intermittently.

For the results you'll have to sign up for my blog.

Quote:

Originally Posted by stewart194

Based on a technical article on this website, I began making a starter with a fresh WYeast pack and I made it 500ml more than I needed for my beer. I put that 500ml of yeast in a sterile mason jar and put it in the fridge. I've done this for my last 3 batches and now have 1272, 1084, and 1098 on hand.

The part that I wasn't sure about, is do I now make a new starter with these 500ml jars and treat them like that are a single WYeast smack pack?

Either way has worked fine for me. Estimating 2 billion cells per ml of thick settled slurry should get you in the ball park for a cell count. (It varies, but for yeast cultured with DME this seems to be about where most of the cell counts lay.)

stewart194 · 01-30-2013, 01:50 PM

Awesome! Thanks! I'll probably just keep making starters out of them and always keep 500ml in a mason jar afterwards. I've read that after 5 or 6 times it's best to start over with a fresh pack of yeast. Something about wild yeasts and other organisms getting into the yeast over time.

stewart194 · 02-01-2013, 11:03 PM

WoodlandBrew -
How can I measure milliliters? I just checked out my yeast stash and all of them have about a 7mm thick yeast cake at the bottom of each jar. They are 1 pint mason jars. They are full of wort / liquid, but the yeast cake itself is only around 7mm thick.

When I filled them, I had just pulled the flask off of the stir plate so the yeast was definitely in suspension if that makes a difference.

Thanks!

WoodlandBrew · 02-02-2013, 12:27 AM

If you have another pint jar use a table spoon fill it to Te same level as the one with the yeast. That will give you a pretty good idea of the volume. Or, if you have a scale that weighs in grams you can use that. One gram is one millilter... Well pretty close one ml is .9983 grams at 25°c if memory serves.

stewart194 · 02-04-2013, 08:30 PM

Thanks! I measured it out this morning and each jar has roughly 3 Tablespoons of yeast at the bottom. 1 Tablespoon is roughly 15 milliliters, so each jar has roughly 45 milliliters of Yeast. 45 x 2 = 90 billion cells. A WYeast smack pack has roughly 100 billion, so that's pretty close. I will always make a starter with the cultivated yeast just to be safe.

Thanks again!

**RIC0** · 02-05-2013, 02:07 PM

Quote:

Originally Posted by WoodlandBrew

I cold crashed my last oatmeal stout just to reduce the amount of yeast. If you have space in the fridge to crash it, I would do it.

Exactly, I cold crash everything just for the fact I can. Also nice having some cold beer to taste before it goes to bottle....