hi i had just posted this inappropriately in another thread, but i will post my experience again here. i can't get cider apples here so on the advice of the above ^^ hbt member senor bathurst and others i have been incorporating crabapples in my ciders this year to substitute for the absent bittersweets in my blend. well, ciders i say- i've only done one so far this year as we are just into apple season. i make many small batches in a year from different apple sources, and i usually don't have access to a press, and i live in an apartment in a medieval city center, so i use the juicer a lot, or else grate and hand press, neither of which is terribly efficient with the apple varieties i use but both methods make for a delicious cider. so for my first crabapple trial i liberated a small bagful of firm golden yellow cherry-sized crabs from a bot garden, refractometer read them at 1.063, stuck them in the juicer and was amazed how well they juiced, the waste was very dry whereas for the dessert apples it comes out a bit wet and has to be run through again or hand pressed to get the efficiency up. so my admittedly long-winded point (i blame the second saturday afternoon orval) is that they are very likely to juice well for you, especially if they are firm when ripe. with my little golden crabs a very small amount, maybe 300 ml in a 5 L batch, gave a noticeable and nice tannin twang to the unfermented juice, but not very much acid, for that i used grannys. i bet yours are less tannin-rich and more acidic from the similar crabs i've tasted, so i'm hazarding a guess that your proposed ratio will be in the ballpark? and if they juice well it will be a snap- a gallon is 4 L- i call fill that using dessert apples in about 20 minutes. as for poaching other apples on your campus- why not? sounds like a forager's paradise; juice them all and ferment!