over the last few days we’ve made a point of trying a different method each day to see what gives us the best result in the Otto, including double loading the basket (i.e. load, tamp, load again into the space created by the first tamp, tamp a second time). Obviously the double load drives the maximum weight of coffee into the basket so a much coarser grind is required. The double load approach might be OK with coffee that isn’t so fresh, but with the fresh Londinium coffee it chokes the Otto very easily.
so far in the experiment we are getting out best result by using our standard weight of 16g in a double basket (or 8g in a single), grinding to the same fineness that we use for the Olympia Cremina, and giving it the lightest of tamps; merely breathing on it with the tamp, else you will choke the Otto completely.
next time we will make our grind fractionally coarser, but still espresso grind to get it running a little faster … we are trying to get into the 80s extraction time for a dble shot that the Otto manufacturers advise… we are still a little outside that zone.
we have posted a photo of this morning’s result on Twitter if you are looking for a visual