Is my washed yeast cake contaminated?

[gonzo brewer]

I have started to harvest my yeast cakes and plan to re-use one this Sunday. This morning I took my WLP-001 out of the fridge to warm up to room temp. I plan to make a starter with this tonight.
There is a thin layer on top that I believe should not be there. The other 3 yeast cakes I harvested do not have this. It should be the tan colored yeast on the bottom 1/4 and clear liquid on the top 3/4, right?

Is it possible this washed yeast is contaminated?

My process for harvesting is using 1 quart of DI water, mix in carboy over yeast cake and let settle for 15 min. Pour into 2 quart glass bowl (cover with alum foil) and let settle for 15 min. Pour into 1 quart plastic juice bottle, cap and place in fridge. I used star san on everything.

 

[Bobby_M]

It's the pour out of the carboy that is suspect. If you use a traditional stopper that slides inside the neck, there's probably some nasties on the lip of the carboy. Did you do anything to sanitize this area before pouring anything in or out? I like to pump the slurry into a sanitized jar using the autosiphon. It's not a big deal since I'm already using it for the beer. I just leave a 1/4" of beer behind to loosen up the yeast first.

 

[gonzo brewer]

I don't use the traditional stopper, I use the Carboy Cap that seals around the outside of the carboy spout.
No, I did not spray star-san on the inside of the carboy before pouring.
I don't have an auto-siphon. I use a regular racking cane and blow into an in-line filter to start my siphon.

So... would you toss this or use it. Is there a way to test by smell??

 

[scottfro]

you could always make a starter with it and taste it....

 

[ohiobrewtus]

I'd be a bit concerned if there's a thin layer on the top. What color is this layer? Has it formed a 'skin' on the top?

 

[gonzo brewer]

So, If I make a starter tonight then taste it in say 36 hours.. if it doesn't taste sour then it is safe to pitch? I've never tasted a starter so I'm not sure what to expect. I supose since WLP-001 is a netrual flavor it should taste like wort.

 

[gonzo brewer]

I'd be a bit concerned if there's a thin layer on the top. What color is this layer? Has it formed a 'skin' on the top?

This layer is a little darker tan than the yeast color at the bottom. It does have a skin over look, similar to the look of the beginning of hydrating dry yeast.