Probably a dumb question, but here goes.... I don"t do anything different, except change grind/grams from one roast blend to another. Yet it seems that some blends start out with a slow stream of espresso going to a faster flow. Normal? One I just started using is very forgiving, (Teodoro)--but starts out a normal flow moving to faster by 25-26 seconds, starting to blonde by then. I don't know if this is how espresso is supposed to flow slower at the beginning, faster towards the end? thanks

If I understand your question correctly, you want to know if it is normal for the flow of coffee to increase as the shot pulls and for different coffees to blond at different times. For flow increasing, yes, that's what I've found. I believe that as the coffee solids come out of the puck the resistance to flow decreases, thus the volume increases. As for blonding, that's tougher. Certainly, if I change nothing else, I've found some coffees blond faster than others. But I've also found that blonding is dependent on the coarseness of the grind, and the amount of coffee in the puck. There are probably other variables too; I suspect that hotter would blond faster than cooler.

Yes, you understood exactly. Good to know. On the roast I'm using now, I tightened the grind just one increment but kept the grams the same. Believe it or not, the shot was 3 seconds to first drip sooner than when I had the grind a tad coarser. So I added more grams, and it took longer to first drip, but still runs faster after a bit. Thank goodness, this is a very forgiving medium-dark roast. I end up adding less steamed milk to my cappuccino so the taste punches through better.