Is the milk you are using pasteurized and/or homogenized? If so, it may be that the floc test just isn't very reliable for you. At least, that has been my experience - with very little access to anything other than store-bought, pasteurized & homogenized milk, I got so frustrated trying to decide exactly when the milk had flocced, because it never seemed to be a very clear and distinct event, and no matter which part of that very unclear event I used, I seemed to get ridiculous answers that didn't seem to translate into actual results as far as the time needed for a clean break. I kept thinking I must be doing it all wrong ... but every description of the process told me I was doing it right ... except it just didn't work.
Then I had the opportunity to use some raw milk. Actually, not even truly raw - I low-temp pasteurized it, and I mixed it half and half with some store bought P&H milk, since I only had a couple of gallons of the raw milk, and I normally make 4-gallon batches of cheese. But even with all of this, the difference was absolutely startling. This time, I had a very clear and distinct flocc, and the time made sense.
Others here seem to have more success with using the flocc method even with P&H milk, so YMMV. Maybe their milk is less pasteurized, or some other difference ... but I came to the conclusion that, with the P&H milk available here, it is not worth trying to use the flocc test. Now I just go by time and clean break test ... and it seems to work out reasonably well for me. Of course, if I can ever arrange a steady supply of raw milk, I will start using the flocc method again!
