What clogs the prefilter at higher concentration?

[ADK_XJ]

I was running my single post system today and took a batch of about 100 gallons of clean sap to 8% concentrate - obviously the machine had to work harder to achieve that concentration but, by the end, it was barely pulling sap through the prefilter and I pulled it to clean at the end of the day to find it was encased in a slimey coating of white gunk.

So, this may be a dumb question, but what IS that gunk? It's not sugar, I imagine. Is it just bacteria and crud? The filter is not dirty like brown but is clearly clogged.

[DrTimPerkins]

Probably yeast. How’d it smell? Did you change the filter before starting for the day?

[ADK_XJ]

Probably yeast. How’d it smell? Did you change the filter before starting for the day? It didn't smell, it was more like a slurry paste sort of texture. This was a fresh filter at the start of the day, I did run about 200 gallons of sap through it that day (it's a single post 4x40).

I did later discover that the filter housing was not seating correctly on the top mount threads and I'm wondering if that was actually my issue, not a blockage. After my latest wash and rinse, I taped the top threads and reassembled it so hoping it pulls much better.

[DrTimPerkins]

I did later discover that the filter housing was not seating correctly on the top mount threads and I'm wondering if that was actually my issue, not a blockage.

I think you have your answer right there.