Search results

Based on those parameters I would estimate that by this time the yeast has already grown to about 5 times, so adding another vial or four isn't going to help much, but won't hurt either. It's probably about 1/4 of the way through. See this calculator that shows growth over time...

If someone else ran the numbers I would feel more confident, but it seem that you just misread the units that I wrote. We are getting the same result. 425 billion cells per liter (not billion per milliliter) is what I came up with for the first cell count, and 460 billion per liter for the...

It's great that you are doing cell counts. Personally, I would have been interested in what the viability was before the starter. It sounds like what you counted is one "box." (this area fits nicely inside the field of view at 400x on most microscopes.) Each box is 4nl. Typically five boxes...

That sounds about right. I'm working on an article that covers some of these questions. I'll make sure to come back with a link once it is available.

Yep, rock solid. The only thing I might ad is that a water bath will help maintain temperatures outside of the fridge.

Typically cell density is 1-2 billion per ml of settled slurry. Closer to 1 if you have a lot of protein from the wort, closer to two if you were good about doing a whirl pool and only transferring the clear wort.

Can "Yeast Washing Illustrated" be un-sticky-ified?

Thanks for finding that mkeckjr. I could see how there may be some thermal introduced excretion if the yeast was still active. Considering that this is from the lagering section that might have been the case. I poked around for papers that might have evidence of thermal related ester...

Well, as long as you sprinkled it across the surface, didn't stir it in, and the temperature was near 80° then viability should be fine.

I'm sorry, I misunderstood. For some reason I thought you were building yeast from bottle dregs. A 1L starter is fine for a vial of old yeast.

I agree with the above posts, but just wanted to answer your question a little more directly. Bacteriologic content can be determined by plating and observing large colony morphology. The presence of some bacteria can often be observed with a microscope. If you see small particles moving...

You're welcome. Feel free to send me a PM or email if you have any questions. For viability and cell density of yeast 400x is all you really need. The 1000x oil immersion is nice on occasion, but I hardly ever use it. I would be a little leery of buying a used microscope without looking...

Your cell density is probably between 1-2 billion per ml. It's hard to tell how big the jars are from the picture. If you can estimate the volume of settled slurry then you can estimate the cell count. If the beer that the yeast came out of was good, and everything used for collecting the...

I don't want to tell anyone what to do, if what you are doing works, I don't want to suggest that you change what you are doing. Measurements I have done on viability show much less loss that what Mr. Malty shows. If you are cold crashing and decanting you might be loosing 1%-5% of your cell...

Here is a blog post I am working on that goes into some details. I need to link the references, but I hope it still explains it well enough: I'm sure Jamil Zainasheff had the best intentions when creating his Mr. Malty Starter Calculator, however it seems that brewers have taken the results...

How long did the yeast float after being added to the wort? You might try the manufacturers instructions for rehydration as well. I've found that works very well both in terms of measured viability, fermentation performance, and beer quality.

Here is the microscope i use: http://www.woodlandbrew.com/2012/11/amscope-binocular-compound-microscope.html

I trust Kai's equation. It is based on cell counts of actual starters done on stir plates and his results were duplicated and confirmed by others. The Chris White equation is based on starters that were not aerated and not stirred and then a "correction factor" was applied based on...

During the typical ale fermentation the biomass increases to roughly ten times the initial cell count. So from one fermentation you'll have enough for about ten batches of beer. Washing yeast, from my research and experimentation, seems to do more harm than good...

If you do find this I'd like to know. After fermentation completes yeast build up their glycogen reserves, the cell membrane becomes less pliable, and their metabolism slows down. I would be surprised if there is any significant ester production or thermal shock excretion at this point.