I tried to make whipped cream with a 500mL dispenser by following the instructions (chill the dispenser for 3 hours, shake at most 7 times), but since I didn't want as much as commonly directed (2 cups), I only used 6 tbsp. However, that led to the cream coming out runny/liquid (Horizon Organic Heavy Whipping Cream, if it matters).
What is the minimum quantity of heavy whipping cream you need to put in dispenser in order to get actual whipped cream out?