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Why are my mash potatoes extremely bitter?!

Just cooked mash potatoes in bulk and they have an extremely bitter aftertaste. There's no way i can eat those. Where did i go wrong?

I cut up 10 organic russet potatoes in quarters
covered them with cold water
brought to a boil
a little sea salt
reduced heat and simmered for 20 min
drained them
in the empty pot I threw in a bit of unsalted butter, organic sour cream ( 1 tsp, 1 tsp cream cheese, and sprinkled a little cheese mix. Oh and a little bit of milk. Simmered that for 1 min, then turned off the heat and added the drained potatoes. Mashed them with a masher.
Where did I go wrong? Could it be burned milk or something?

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    1. re: GH1618

      No I never peel potatoes and they are never bitter like that

      1. re: Mustardeer

        They were this time. If you are going to boil russets, you need to peel them and be sure to remove any green areas to ensure that the result will not be bitter.


        1. re: GH1618

          I use Yukons more than Russets, and normally don't peel them. But, by themselves the skins can be a bit bitter.

          Read about solanine in potatoes
          "Showing green under the skin strongly suggests solanine build-up in potatoes, although each process can occur without the other. A bitter taste in a potato is another, potentially more reliable indicator of toxicity."

          1. re: GH1618

            The green part can also make you sick.

            1. re: C. Hamster

              My potatoes were dark brown so they might have had a green tint that i didn't notice. I kept them on the lower shelf in the fridge. From now on I'm gonna start peeling them just in case. Ahh! It's gonna take forever to peel all of them, bummer.

              1. re: Mustardeer

                Potatoes should not be stored in the fridge. They should be stored in a dry cool place away from heat sources.

                1. re: Ruthie789


                  Harold McGee in Keys to Good Cooking:
                  "Keep cold-sensitive vegetables at cool room temperature to prevent damage or sprouting. ... potatoes to be used for frying, which when chilled accumulate sugars that cause them to brown too quickly." p147

                  That sounds like a qualified reason. Chilling affects the starch/sugar balance, but does not otherwise harm the potatoes. Light is more of a problem.

                  In my apartment, the fridge is the darkest cool place. Lately I have been using a cooler on the porch to store a 15lb bag. It may not be as dry as ideal, but it is cool and dark.

                  1. re: paulj

                    I believe that affecting the starch balance causes the potatoes to lose some moisture and they are not as good when mashing. Once they sit on the counter to room temperature they do not seem to rehydrate, that is my experience with potatoes used for mashing when they come out of the fridge.

                    1. re: Ruthie789

                      I'm sold, from now on my potatoes won't go near the fridge.

                      1. re: Ruthie789


                        repeats the starch to sugar issue, and claims the ideal temperature is 42F, a bit warmer than a fridge.

                        1. re: paulj

                          I disagree about the fridge and so do many cooks. Potatoes should not go in the fridge. I did some research on the internet, some sources do say you can store in the fridge but also indicate that they can never be stored below 4 degrees celsius as the starches will turn into sugar and alter the taste of the potato.
                          I give two sources below:

                          1. re: Ruthie789

                            Is that bad? I haven't noticed that my potatoes tasting sweet. I haven't noticed the excessive browning that HM cites, though I boil my potatoes more than I fry them.

                            From one of your sources:
                            "A. At 7-10°C (45-50°F) potatoes will keep well for several weeks. At temperatures much over this, potatoes will not maintain freshness for more than one week. Warmer temperatures encourage sprouting and shriveling."

                            I prefer a sweetening that I don't notice over sprouting that I can see.

                            1. re: paulj

                              To each its own, I do not like the texture of refrigerated potatoes, it does change their structure. And yes I agree sprouting could be a problem, so I buy less and more often.

        2. I think it may be your sour cream, why not just milk and butter?

          4 Replies
          1. re: Ruthie789

            The sour cream was brand new i just bought it this morning. Could 1 tsp of great tasting organic sour cream really do this to 10 potatoes?!

            1. re: Mustardeer

              No a simple teaspoon of sour cream would not do this to your dish.

              1. re: Mustardeer

                Not being snarky but can you even taste one teaspoon of sour cream with ten potatoes?

            2. What, exactly, is "a little cheese mix"?

              1 Reply
              1. re: Jay F

                365 ( whole foods brand ) unexpired organic shredded italian blend

              2. I use sour cream on occasion and have not noticed a bitter flavor. As long as your ingredients are fresh, I'm wondering if the problem may be something like a lingering residue in the pot that you used, or the quality of your tap water. I know some places have tap water that may be potable, but still has a horrible taste. Other than that, did you rinse the potatoes beforehand? If not, some soil or debris may have been present. I'm grasping at straws here, but in my opinion, the ingredients you listed should yield an acceptable product.

                1 Reply
                1. re: d8200

                  Just tasted my tap water it seemed fine
                  There might have been a tiny bit of residue in the pot but it looked pretty clean to me. I rinsed the potatoes beforehand.

                2. More importantly anything I can do to undo this horrible aftertaste or do i trash them?

                  3 Replies
                  1. re: Mustardeer

                    I would try adding more dairy and more salt - salt can be a good masker of bitterness. In fact, if you didn't add salt in the first place that's probably your culprit.

                    1. re: Mustardeer

                      I hope you trashed them. Wish I'd seen this earlier. Solanine poisoning is no joke, and the bitter taste is a solanine "marker."

                      1. re: eepi

                        Sure did. They were so disgusting no salt could have saved them.

                    2. Were any of your potatoes green in spots?

                      2 Replies
                      1. re: sr44

                        No they were about 5 days old and looked great. There were a few tiny black spots that I got rid off with a parng knife.

                        1. re: Mustardeer

                          I thought you meant green on the inside. I guess they might have been greenish on the outside don't remember but they were definitely yellow on the inside.

                      2. If you have any potatoes left, duplicate the cooking method in a different pot. Drain and taste them. This will tell you if the potato itself is the source of the bitterness. If so, it could be from naturally occuring metals and salts in one small patch of a field.

                        Next I would blame residuals in the pot. After that a bad cheese mix.

                        1 Reply
                        1. re: INDIANRIVERFL

                          that sounds like a great idea except I cooked all of the potatoes in the bag

                        2. Just tried another bite. So they taste great at first. Then after about 3 seconds the bitterness kicks in, then after about 7 seconds there's this awful feeling in my mouth that stays for a few minutes. Like really bad not just barely there.

                          Forgot to mention I used a bit of black ground pepper could that be it? I turned my vintage peugeot grinder twice over the entire pot.

                          3 Replies
                            1. re: Mustardeer

                              Did you eat Pine Nuts in the last day or two? If so, do an advanced search on CH for pine nut aftertaste, or "pine mouth".

                            2. The bitterness could come from the potatoes. Sometimes potatoes can accumulate total glycoalcoloids (TGA) called solanine or chaconine. They would come from the presence of chlorophyll. This is why one poster asked if you saw any green on your potatoes.

                              Given that you did not peel the potatoes, if they did have excess TGA you'd notice a pronounced effect because most of the TGA accumulates on the peel.

                              If the potatoes were exposed to significant light during storage that could indicate high TGA.

                              1. Although pepper can be bitter, I think it was the peel.

                                Did you taste the sour cream and cream cheese before you added them?

                                1 Reply
                                1. re: C. Hamster

                                  Tasted both and they were both amazing. Both organic and brand new.

                                2. That greenish tinge people are talking about is pretty much right at the peel,so not really noticeable if you don't peel them. I"m not sure what happens to the green after cooking; I always peel and dump if greenish, As far as I've ever seen, it doesn't go deeply into the flesh.

                                  1. I had the same problem with farmers market potatoes last spring. They were new potatoes, there was no green, and they looked fantastic. I boiled them and drained them as usual, and left them in the colander to cool. When I came back, they were horribly bitter. I think they must have had light exposure, but for some reason they didn't turn green. But that caused a solanine buildup anyway. When I read your post, it sounded exactly like the potatoes I had. But I hadn't put anything in them, so there was no question about whether it was the potatoes or something else. Weird! So, I now taste potatoes after I boil them, and before I do anything else with them :-)

                                    1 Reply
                                    1. re: jessica001

                                      that's very helpful, I'll do that from now on, thanks!

                                    2. Potatoes belong to a poisonous family and the skin contains a bitter substance, which is set free by the heat and goes off with the steam, provided the potatoes are opened or uncovered as soon as done. If not, the potato absorbs it and becomes bitter.