unripe apples?

This year the apple harvest is sadly not very good and many apples dropped early.

I've juiced and frozen the juice, but would it be possible to use these for cider?

There is no reason you couldn't use that juice to make cider. If you have any concerns about any bugs, try sulphite.

From what I've read, unripe apples should be avoided. Too starchy resulting in flat flavors.

While I'm pressing some ripe apples now (early ripening varieties), I'm also seeing lots of "unripe" drops due to heat stress, as Oregon experiences a record hot summer. More so than normal, I'm relying on taste and presence of black seeds to determine ripeness and suitability for pressing.

--SiletzSpey

Pick then up, box them and store them somewhere cool and dark and they will ripen a bit, but maybe not enough.

I got a couple gallons of juice from some early apples last fall, and the juice was used to make a cyser that came out palatable, but dryer than I would have liked and with a somewhat dusty taste. Since I had never had a cyser before, dunno if that was normal or otherwise, but it is tolerable enough.

May be that the best you can do with them is use them to take some of the edge off some too-sweet dessert apple juice.

Experiment!

TeeJo