Three weeks ago I racked and bottled some perry. Before bottling, I filtered it through a kitchen cloth. I added a teaspoon of sugar per bottle.
With the exact same approach, I got a rather foamy apple cider. The perry however is rather flat, hardly any carbonation.
After filtering, the perry was rather clear. I suspect that for some reason there's not enough yeast in the bottles and I plan to add some. But are there other possible reasons?