Separating terumot and ma'aserot from unripe avocados
Question
I picked about 10 avocados last week and brought them home. Do I have to wait till they are soft and tasty to separate terumot and ma'aserot? I think you can eat them unripe though they are not tasty.
But if I cut an unripe one for terumot and ma'aserot, I will have to throw away part since once cut, avocados no longer ripen.
Also what do they do in supermarkets where terumot and ma'aserot have been taken but the avocados still need a week or 2 before they ripen and can be eaten?
Answer
In the case of unripe avocados, their growth on the tree has ended and they require time for them to ripen. It is possible to expedite this process through artificial ripening methods, such as using ethylene gas found in apples, or other means. However, since the avocado's growth on the tree has concluded, halachically it is considered ready for consumption. It is not lacking time to grow on the tree, but rather other factors. Therefore, separating terumot and ma'aserot from an unripe avocado is permissible, albeit challenging.
This is analogous to a potato, which cannot be consumed raw and requires cooking. From the perspective of growth time in the ground, its growth has ended, but it still requires a cooking process. However, halachically, one does not need to wait until after cooking to separate terumot and ma'aserot from it.
Similarly, one need not wait for bananas to soften before separating terumot and ma'aserot.
Since there is no need to wait for the avocado to soften, in supermarkets, terumot and ma'aserot are separated from avocados while they are still firm. At home, it is always preferable to separate terumot and ma'aserot as soon as possible, even when the avocado is hard, and even if it means discarding a whole avocado. Theoretically, one could wait until the avocado is ripe before separating terumot and ma'aserot, but this is not preferable, as there is a concern that one might forget to separate terumot and ma'aserot later on, risking inadvertently consuming tevel (untithed produce).
A tip going forward: You can save the part of the avocado you would otherwise throw away (not the part you designated as terumot) from this batch of harvest, clearly tape a label to it "tevel," and save it for the 1% separating terumot from your next batch.
I know someone who does this on a regular basis: from each batch, he saves one avocado, clearly labeling it tevel, for separating terumot and ma'aserot from the next harvest. By the next harvest, this avocado is already soft and fully edible. He now can cut into it and use the rest of the avocado, thus avoiding throwing away an entire avocado each time.