My second Colby effort

[DeejayDebi]

Well you already reduced acidification time so maybe try a bit less starter.

[Boofer]

I used 1/4 tsp Meso for this and the wayward 2nd Gouda. Both cheeses were washed curd which should also have reduced the acidification. I could try to cut the Meso to 1/8 tsp and maintain everything else for control.

-Boofer-

[Sailor Con Queso]

Based on your texture, I would say that you definitely need to increase your pressing weight and/or pressing time. Too little pressure will leave whey that can turn sour.