Empty stomach?

How long after a meal does it take before you can say your stomach is
empty? I know it depends on the amount of food of the meal, but what's
the range, like 30min-90min?

I'm asking because I want to start taking ZMA. Problem is the instructions
say to take on an empty stomach about 30 min before bed time. My
schedule is that I go to the gym around 7:30 pm after work, get home
around 9pm and start preparing dinner. I usually then don't eat until
9:45-10 pm and finish dinner at 10:30. I go to bed around midnight. That
gives me about 1 hour from the time I finish dinner to the time that's 30
min. before bedtime. Enough for the stomach to be considered empty?

amount and type of food

some things such as vinegars, soluble fibers, fats might slow gastric emptying significantly

coach hale

A full stomach of water can take about 20 minutes.