Depending on the amount of pressure in the initial press, we find it's possible to press the material up to three times. We do this by ramping up the pressure of each press. It's important to note that we do this while the material is still warm if the material is allowed to cool the yield and smell can be affected drastically. We do find the rosin can be of a lower quality at the second and third press so we do like to keep them separate but we include these in the yield for our overall number. By pressing up to three times we saw the yield consistently come in around 20-25% for dried herbs and 60-90% for extracts. Yield and quality can vary widely depending on the quality of the starting material, so we like to test smaller amounts first to determine if the material is even worth pressing.
When we do multiple presses we try to take notes so we can better understand our limits. Things we like to track is the time, temperature, and psi of each press. As we ramp up the pressure on each press we like to watch the temperature and pressure to help us better understand when our bags will blow-out or when the parchment paper will start to deform. These notes are great if we'll be pressing larger amounts as it allows us to process our rosin more efficiently. Sometimes we find that a third press is undesirable due to the lower quality and yield we've experienced. For this reason most of the time we just skip the third press entirely. We actually only press our material twice because we like to use the leftover material to make other things like edibles or topicals. In some situations, we've found a third press is actually beneficial. This is why the third press is always included in our initial test because no starting materials are the same. The details of our notes include the starting materials moisture, color, age, quality, and quantity. The more descriptive we can be the better we can hone our skills, so we're not afraid to overdo the notes.