Press by Daryl

[HowardR]

I learned something about the black diaphragms -- replace them when the woven reinforcing material tears. Last year I replaced two of them, right after they tore, worried that, if I didn't, the diaphragm would get a bubble or hole while I was in the middle of pumping the next batch. This year I tried not replacing one to see what would happen, and on my 4th batch, the second of two 6.5 gallon batches, the first batch in which the pumping got tough at the end, the diaphragm developed a bubble when I was pressing out the last quart and popped when I kept pressing.

I need to figure out how to avoid ever tearing the woven reinforcing material on top of the black diaphragm. It doesn't tear when I am pumping hard; something else causes it to tear. I have two hypotheses about what causes the woven reinforcement material to tear:

1. Pressing two hot. I've usually been pressing between 200-210. With this next diaphragm, I'm going to always press just below 200.
2. Letting a bit of water get on top of the diaphragm. Sometimes when I wash the press, I leave a bit of water on top of the diaphragm. It seems like, whenever it tears, I see water on top of the diaphragm. It could be that the temperature difference between cold water on top and hot syrup inside causes the diaphragm to tear. I'm going to be careful to make sure the diaphragm top is dry before I press in the future.

Hopefully, with these precautions, I'll be able to get more use out of each diaphragm.