Deb, That seems a little harsh. I don't feel that's exactly an "error" in her book, just a difference in approach.
My intent was to point out that the curdling (flocculation) time method is just a lot more scientific, accurate, and consistent. It takes into account a LOT of milk and environmental variables that simple time-based approaches can't adjust for. For example, I used fresh raw milk that was litterally less than 2 hours from cow to stock pot. The fact that it is raw AND was never refrigerated changes the dynamics considerably. (YES refrigerating does make a difference). Pasteurized store bought milk might fall in line exactly with her timing, or certainly much closer. Her recipe calls for low fat (2%) milk. After skimming cream etc., my milk was probably closer to 3.5%. Since she is using a lower fat milk, a longer curdling time always gives a little more moisture in the finished cheese and might give better curd volume. At 3.5%, I'm sure my Parm didn't need the extra time and moisture. My raw milk probably has a lot more calcium than a 2% pastureized, so my floc time is probably a lot quicker. In fact, since I have been using the curdling time method, I have cut my animal rennet by about 25%, and still get amazing curd set with raw milk.
I looked at several Parm recipes that used a similar curdling time as hers. I think "open to interpretation" is exactly what we SHOULD be doing anyway. Ultimately that's what makes us cheesemakers and not just side-order cooks blindly following a recipe. Add a pinch of this, a dash of that, heat to X, and stir until done - what's the fun in that???
YES... I'm sure she has made lots of cheese.
