[denny]

Has anyone ever experienced an infected starter?  If the yeast starts out infected, then I can see an infected starter, but if typical, reasonably healthy yeast is used I think it would be a very, very remote outlier....

Happened to me once when I used a questionable slurry.  It was poor judgment on my part. I knew better and used it anyway.

[Saccharomyces]

How can you see if a shaken starter is infected? You could taste the one made on a shaking plate after a cold crash.

You can taste an SNS starter.  However, smell is a better sense for infection than taste.  There is no need to cold crash to determine if a starter is infected.  Nine times out of ten, infected starters usually have something growing on the surface that is not yeast.

[filipp]

Thanks. I'll start a shaken starter tonight. 0.5 liters for a batch of 12 liters. I hope it's ready in 16 hours.

[Saccharomyces]

Thanks. I'll start a shaken starter tonight. 0.5 liters for a batch of 12 liters. I hope it's ready in 16 hours.

One does not need a starter for 12L of wort.  The amount of yeast in a White Labs package contains enough viable cells to ferment 12L without propagation.

[filipp]

I start with a little recovered yeast.

[Saccharomyces]

You are making life more difficult than it needs to be. If you are using recovered (a.k.a. cropped) yeast, you do not need a starter either.   A starter is waste of time when using cropped yeast that is less than six months old.  You just need to collect a large enough volume from your fermentation vessel that there is around 100ml of sediment (slurry) after the solids settle for a 12L batch.  On brew day, pour the supernatant (the liquid that rests above the solids) off before pitching the sediment.  I created the SNS starter technique. I never use a starter with slurry.  That defeats the purpose of using cropped yeast.


Here is what cropped yeast should look like after it has settled:



The liquid (supernatant) is discarded before pitching.

[filipp]

So far I have only worked with dry yeast.
At the end of a batch I split the remaining yeast in half. Half I used it directly in another batch and half I washed it. That's how I was left with only a little yeast on the bottom of a jar. That's what I want to start the starter with.

[Saccharomyces]

So far I have only worked with dry yeast.
At the end of a batch I split the remaining yeast in half. Half I used it directly in another batch and half I washed it. That's how I was left with only a little yeast on the bottom of a jar. That's what I want to start the starter with.

One should know is that you should never rinse yeast with water (actual yeast washing is an entirely different process that uses acid to kill off wild microflora)  I covered the reasons a couple of years.  It is always better to store cropped yeast under the beer from which is was cropped than to store it under water.  Water provides zero protection for the culture.  On the other hand beer has a low pH and ethanol.  Rinsing yeast with water is probably one of the worst practices ever propagated within the amateur brewing community.  Like a lot of dogma, it is difficult to kill. 

That being said, the yeast in the Erlenmeyer flask above is cropped BRY-97, which is dry yeast.  To obtain a crop that clean, one has to leave at least 500mL of beer behind while racking (I always formulate my recipes so that I can leave around two liters in the kettle with the break as well as a liter behind in the fermentation vessel).  The sediment in the fermentation vessel is swirled into suspension and then allowed to rest for a couple of minutes before decanting only the liquid portion into a sanitized container.  This process pretty much guarantees that a yeast crop is for the most part hop and break free.

[filipp]

Thank you for your help.
I tried to wash the yeast just to see if I could work clean. I told myself to use it if I still succeeded.
Now I'm reading about keeping yeast under beer.

[filipp]

Eventually I made a 0.7 liter starter for a 14 liter batch. It reached high krausen in 12 hours and I had to put it in the fridge for a few hours until I finished the day of brewing. Did I notice activity in the airlook after 7 hours? It's fine?
I know there are several factors that influence it but what is the average period for getting out of the lag phase?

[filipp]

It seems that the topic is no longer of interest, no one answers us anymore ... but I try to shake the starters.
I started the second attempt of shaken starter: I inoculated the yeast around 1 pm and the activity in the airlook started around 8 pm. The next morning there is a real madness in the airlook.
I used a 0.9 liter starter for 13 liters of beer. An OG of 1,060.
I hope there isn't too much yeast.

[Saccharomyces]

You are doing fine.  It just takes a little while to get a feel for timing.  Soon, making an SNS starter will be second nature to you.

[pete b]

I often don’t get the timing exactly as I would like yet it always works great. Horseshoes, hand grenades, and as Mark likes to say, nuclear bombs: close enough is good enough.