How can I know whether a potato is too old? I have many kilograms of potatoes that are turning bad, I don't want to throw them away. The term "turning bad" means that the best-before days on the products vary between 1-4 weeks i.e. they are old from 1 week to 4 weeks. Some of them taste bitter, some of them taste good but some black while some sprouting and other shape-changes. I am not looking for recipe recommendations, rather how to manage this problem. How can I know whether a potato is too old to be edible? If I can understand right, some sort of acid is formulated in some potatoes. Hence, I think I cannot cook the same products with them as with non-acidic potatoes. How should I manage acidic/non-acidic potatoes differently? Can I add some base to neutralize bad potatoes so they would become more edible?

Related Question but not the same


Are green potatoes OK?
Is it safe to eat potatoes which have sprouted?
It likely depends on what 'turning bad' means ...

If you have a couple in the bag starting to sprout, but the rest haven't, you can roast or bake the ones that haven't sprouted, let them cool, then store then in the fridge so you can pull them out to use them in something later in the week.  (eg. home fries, patatas bravas or a hash).

For those that have started to sprout, but are still firm, you can cut away the sprouted bits (this time of year, you might even be able to plant them), peel them, and then boil them and turn 'em into mashed potatoes (which you can then vary for the next couple of days ... you can mash 'em with other stuff to make a sort of potato salad; you can add cooked greens to make colcannon or bubble and squeek; you can use as a topping for a cottage pie (the technically correct term for shepherds pie when you're not using mutton or lamb)

Some of these freeze well ... I've made up cottage pies and frozen 'em in oven-proof containers; you could likely do the same with just mashed potatoes -- I see 'em for sale in the grocery store all the time.

If you're looking for something to cook that just uses a lot of potatoes (in a non-whole state, in case you need to cut away parts) ... potato salad, potato bread, potato curry, latkes, potato soup, tortilla de patatas ... the list goes on. 

... and if they're soft and squishy, or oozing liquid ... pitch them.  They're rotting, and not worth getting sick over.