There is no definitive answer to this question as the amount of espresso in a bottomless portafilter can vary depending on a number of factors, such as the grind size of the coffee, the dose of coffee used, and the brewing method. However, a good rule of thumb is to use around 18-20 grams of espresso for a single shot, or 36-40 grams for a double shot. If you are looking to make a large batch of espresso, you may need to adjust the amount of coffee accordingly. Experiment and find what works best for you!