Technique
Dissolve sugar before chilling
Blending the sugar with liquid before adding ice gives the grains a chance to dissolve.
How to do it
Put the lemon juice and sugar in the blender jar; keep the zest aside. Fit the lid and blend. Stop the blades and unplug the blender before checking. Use the tasting spoon to take a small sample, then rub it between clean fingertips; it should no longer feel sandy. If grains remain, replace the lid, reconnect the power, blend briefly, then stop, unplug and check again.
If it goes wrong
If sugar grains remain, keep the ice and zest out, refit the lid and blend briefly again. Stop and unplug before each spoon sample; do not reach into a running blender.
