Testing Geo

[Lloyd]

Been making my Cams for a while, and was quietly pleased with myself that a wasn't seeing slip skin anymore, and was getting a good coverage of PC.  However I've not tasted one for a while, as demand for them has been faster than I could produce them. Today I cut one open, and although the taste was just what I wanted, there was no sign of runniness, and in fact the paste was speckled with small holes.  Recently I've thought they were firmer than they used to be.

I'm suspicious that my Geo is no longer viable.  Its been in the freezer in powdered form for quite a while, and I wonder if it has expired. Does anyone know of a good way to test it?

Any other thoughts on the situation?

Thanks

[GortKlaatu]

Hmmmm. Have you changed the subtype of your P candidum recently?  I ask because if you're not having slip then I would think that the Geo is working. My understanding is that it is the subtype of P candidum that is more responsible for proteolysis than the Geo.  I know when I used the same Geo but changed my PC, I got much different results.

[Lloyd]

Don't believe I have changed either the pc or the geo. I've always assumed that the white covering was caused by the pc, have in got this wrong?

The only change I have made, and I don't think it coincides with the issue, is to defrost the starter before adding, rather than adding frozen. This does mean that the pH decreases faster.

[GortKlaatu]

Geo does affect the flavor and ripening, but it's primary purpose, when used in conjunction with PC, is to work synergistically to reduce foreign mold growth and to adjust the pH to make it very hospitable to the growth of the PC and in so doing, helps prevent slip. The proteolytic activity of the PC  affects the "runny-ness"...more proteolysis more goo....the lipolytic activity of the PC breaks down the fatty acids and affects flavor...the more lipolysis the faster and stronger the flavor develops. That's why various strains of PC affect the cheese differently

[Lloyd]

Ok. So everything that has been said suggests to me that there is nothing wrong with the pc or the geo.

My other thought is moisture content. I wonder if I'm stirring the curds more than I used to, so they are losing more moisture?

[GortKlaatu]

Another thing:  Have you changed milk?  That can do it, too.

[Lloyd]

In theory the same milk (but it's not direct from the farm).

Just looked at my records and the batch in question has the lowest yield I've ever had, so at the moment I'm leaning towards over stirring. The three batches that are currently maturing were all stirred for less, so I'll have to see how that are in the next few weeks

[GortKlaatu]

Keep us posted

[Stella]

Your geo sounds ok, the holes might be from over active starter I didn’t notice which hemisphere you’re from, but summer can affect starters.