I made some farmer cheese (heat milk, add vinegar, strain curds). I didn't have a strainer big enough to handle the whole batch, so I used two smaller strainers. Weirdly, the two sub-batches produced very different-looking whey (see photo). Why would this happen, and are both batches of whey safe to consume?
Neither batch looks like the color would, in and of itself, look worrisome for the whey pressed from farmer cheese. If there are no other worrisome factors (like an off smell, or unsafe handling), then I would probably assume that the whey, and the cheese, is safe to eat - though your risk tolerance may vary.
As for why the batches look different - it looks like one batch still contains some milk proteins emulsified in it. I've seen very milky looking whey (it happens when the curd didn't set cleanly), so again, by itself it wouldn't make me hesitate. I notice that that batch also looks bigger - which might just mean your batches were unevenly split, but could also indicate you got a little less of the milk proteins out of that batch, more remained to color the whey, and you perhaps got less curd out of that batch.
As for why the batches came out differently, I can only speculate. It could be one batch had a bit longer to cure than the other (while you were processing the other batch, perhaps), so the curds with a bit more time separated from the whey a bit more cleanly. It could be that the milky proteins were kind of hovering more at the top, or else settling down at the bottom of the curds-and-whey mixture, and so when you were pouring it into the two strainers, one poured clearer and one got all the extra milky coloration. It could be that one strainer had a better filter to catch the milky proteins, or one strainer pressed harder and wrung out more of the whey - including those extra proteins.
If I'm right, then the whey on the right (whiter and more volume) should be able to be curdled again into some kind of whey cheese, to get the rest of the milky proteins out of it, while the one on the left would produce much less (if any) if re-curdled.
Again, you should be wary, and discard if there's off smells, tastes or textures, or if you have reason to believe the milk, cheese, or whey was unsafely handled. But if the only difference is the color and proportion of leftover milk proteins, then both batches should be safe to use.