Rinse Spinach well - I grow my own and I don't spay it with any pesticides, so I'm mostly concerned about getting rid of soil, and bugs. If you buy it in the grocery store be sure to wash it properly. I use Triple Orange Bio Sanitise to do a good job to clean my store bought vegetables. (It's high on the Dirty Dozen list of foods containing residual pesticides)
Put 1 pkt of 300g rinsed spinach in a big saucepan with nothing else but the water coating it from the rinsing
Put the lid on
Remove and place in colander Repeat with remaining 600g
When cool prepare your chopping board, knife and bowl for the spinach juice
Remove the thick stems. You can cut the out at the beginning before you cook. But I think it's easier at this stage. I grip the stem in my left thumb and run my right thumb and forefinger down the stem to remove the wilted leaves
Take a handful of leaves and squeeze all the moisture out of the spinach. This is the most important step
Look at all that spinach juice
Keep the stems to use in stews, soups, casseroles. You can also make a cheese sauce and serve as a side dish.
Chop the spinach
Total original weight of spinach 900g after cooking this is the yeildstem weight 215gleaves 305gjuice 366g Do not throw away the juice. Drink it or add to soups or smoothies. It's not cappuccino but it's really good for you.