althalos
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- Feb 3, 2009
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I am a yeast researcher, so I store my brewing yeast long term in -80C. When I get ready to make my starter, I take a swipe of yeast and plate it on a YEPD plate, which is comprised of yeast extract peptone, peptone, and dextrose (essentially dead yeast components, proteins, and corn sugar). This is standard in the lab. Once the yeast has grown up at room temperature on the plate, I take a colony to make a starter out of it using DME and a little fermaid-k. All the beers I have done this with have had an odd solvent/fusel alcohol taste to them. I use a counterflow chiller and do not separate the cold/hot breaks before going into the fermenter (I just stick the cold wort exit tube into the sanitized fermenter). I am confident that my sanitization, brewing temperatures, time at which I transfer to secondary, etc. are all on point.
I think the flavors could be a result of the plate I was growing them on, because one time I made the starter in a similar way (yeast extract, peptone, and maltose), and centrifuged the yeast to pitch, and the solvent flavor was so bad I had to scrap the entire batch.
However, the flavor could also be a result of not separating the trub after counterflow chilling, i.e., putting it into a separate container, letting the trub settle, and siphoning off the top.
Or it could be a combination of the two.
Does anyone have any recommendations? I think next time it would be a good idea to plate on a DME/agar plate, and transfer to a DME liquid culture, and separate the trub after fermenting.
Any help is greatly appreciated.
I think the flavors could be a result of the plate I was growing them on, because one time I made the starter in a similar way (yeast extract, peptone, and maltose), and centrifuged the yeast to pitch, and the solvent flavor was so bad I had to scrap the entire batch.
However, the flavor could also be a result of not separating the trub after counterflow chilling, i.e., putting it into a separate container, letting the trub settle, and siphoning off the top.
Or it could be a combination of the two.
Does anyone have any recommendations? I think next time it would be a good idea to plate on a DME/agar plate, and transfer to a DME liquid culture, and separate the trub after fermenting.
Any help is greatly appreciated.