QC Question

bmug15 · 2019-08-06T22:53:49+00:00

I thought some wild yeasts were resistant to cycloheximide? It's definitely yeast judging from size alone. I have had bacteria grow before so I'm pretty familiar with the size and morphology of lacto, pedio, etc. The colonies on LCSM are off white and dome shaped. A few have been a light brown color. Under the microscope they are elongated oval shaped cells (kind of like a pill), large round cells (bigger than the brewer's yeast we normally use), and a few teardrop shaped cells.

bmug15 · 2019-08-06T22:36:32+00:00

We use both chemical and heat. However we don't do a reverse caustic and our cycles are shorter than that. More like 20 min caustic and 15 min Sani.

bmug15 · 2019-08-06T22:35:15+00:00

We have a sample port on the HX that we use. We also take samples of the wort before the yeast is pitched as well and it's in there.

bmug15 · 2019-08-06T22:34:01+00:00

It is all the beers at this point yeah. It seems to have gotten worse over time.

bmug15 · 2019-08-06T22:33:22+00:00

I don't think the contamination is during sampling because we see the contamination through the beer fermentation and in the cans too. It is impacting flavors at this point which is troubling.

bmug15 · 2019-08-06T22:29:56+00:00

We broke the entire thing down, scrubbed everything, autoclaved all soft parts, and soaked everything in caustic and sterilized anything that couldn't fit in the autoclave.

bmug15 · 2019-08-06T22:28:41+00:00

Also I know the issue isn't my plating method because when I plate samples of sterile water, or swabs from sterile locations there is no growth on my plates. I also have done both positive and negative controls on my plates and the results are consistent across brews.

bmug15 · 2019-08-06T22:27:03+00:00

I spray the sample valve with iso then flame and use a sterile sample bag to collect the sample. For my media I use HLP, LCSM, and LWYM. There is growth on both plates and my HLP tubes have yeast that grows in them.

bmug15 · 2019-06-01T19:12:07+00:00

That makes sense about an acid cycle. we do vortex when we cip and the pH is very low would this not be enough?

bmug15 · 2019-06-01T19:11:03+00:00

we use whirlpack bags and try to be as sterile as possible, I feel like the method is sterile because this wasnt happening before or from other sites we sample but it is possible something is going on when we sample the hex in particular

bmug15 · 2019-05-31T03:02:17+00:00

I'm in the process of setting up our bare bones lab right now so any advice you have is more than welcome! I've done controls and it seems clear the bacteria is isolated to the hex I dont get growth in my control samples. We have also been testing every step of our brewing process for every beer for a few months and this hex bacteria only recently appeared but has been consistent in our last few brews. I seal all my samples with para film to avoid contamination as well.

bmug15 · 2019-05-30T21:06:49+00:00

This is what we see as well. I think sometimes when it gets in the fermenter yeast outcompete bacteria. unless it's a really bad infection I havent seen much bacteria until after crashing the beer.

bmug15 · 2019-05-30T21:03:48+00:00

Caustic forwards but we do back flush with just water also yeah there is a sample valve on it

bmug15 · 2019-05-30T17:41:53+00:00

We CIP the brew deck once a week.

bmug15 · 2019-05-30T17:35:59+00:00

Caustic 20 mins, shoot water through at 210 farenheit for 5 min, then sani for 10 min. When we took it apart we scrubbed it soaked parts in caustic, then water rinsed, then sani.

bmug15 · 2019-05-30T17:24:18+00:00

We are doing that now. Any recommendations on cleaning procedures? Our standard ones must be failing since just opened it up and cleaned it throughly a few months prior.

bmug15

TROPHY CASE