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Resting potatoes in water pre-cook

I remember my mom cutting up potatoes for mashers and letting them sit in cold water as she finished other "mise" chores.

What are ramifications of doing this? How long before it's a problem? She makes great mashed potatoes btw.

Not sure how "absorbent" potatoes are...

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  1. Its done to wash some of the starch away. I don't believe the potatoes absorb water.

    1 Reply
    1. re: primebeefisgood

      We do it just to get a head start on prepping dinner, when we've got a lot to do, and to keep the cut potatoes from browning once they are ready. When I am making mashed potatoes immediately (e.g., for dinner on a weeknight), as soon as the potatoes are ready, I start them on the stove.

    2. I believe that the only adverse impact is that it might cause water soluble nutrients to leach out. On Thanksgiving, it's not unusual for our potatoes to be peeled and cut-up, sitting in the pot in water, hours before we cook them. No adverse taste consequences that we've ever noted.

      6 Replies
      1. re: masha

        I'm going to serve mashed potatoes (and other stuff) Wed. Don't want to be doing this same day with so much to do. Do you think they will suffer if I made them the day before, refrigerate, then reheat for the dinner?

        1. re: walker

          Yes, if you make them ahead of time and then reheat they will definitely suffer. However, you could boil the potatoes al dente, refrigerate, then reboil till done and proceed from there. Reheated mashers are easily recognized.

          1. re: primebeefisgood

            I'm going to respectfully disagree with you. A few years ago for Thanksgiving I did the MPs the day before and reheated in the slow cooker. People were stealing fingerfuls straight out of the pot :) 'Course the fact that they were laden with butter and heavy cream MIGHT have had something to do with that :)

          2. re: walker

            There is a mashed potato 'casserole' that I've made for Thanksgiving for years - cream cheese, sour cream, a dash of garlic, some parm, some milk, mash it all together, put it into a casserole dish. Refrigerate over night, bake at 350 til hot through. It's very popular in our Thanksgiving crowd.

            1. re: jeanmarieok

              I'm going to buy about 20 Yukon Gold potatoes for 8 people (we like leftovers!). I'll mash w/1/2 & 1/2 and butter. How much of the rest would you suggest I add?

              1. re: jeanmarieok

                Sounds similar to this Barefoot Contessa recipe for Parmesan Smashed Potatoes. I have made this many times, put in a casserole dish and reheated the next day with great success. They are amazing...of course, anything with this much butter, half & half, sour cream and parmesan cheese has to taste good.


          3. If they are to be boiled, then it doesn't matter if they absorb water. Leaving them this way overninght, not really a problem.
            I've seen this done with potatoes destined to be latkes--it keeps them from browning in the presence of air.

            1. I do this all the time with potatoes used for oven fries. Prevents them from browning

              1. I sometimes do this with potatoes destined to be fries, although I add a little sugar to the water.

                When I was growing up, I remember all veg prep used to be done on Christmas eve for christmas day, including the potatoes, which were left to sit in water. Nothing bad ever came of it.

                1. it's also done because some varieties of potato oxidize (like apples going brown) and turn a really unappetizing, funky grey color.

                  Submerging them in water prevents them from coming into contact with air, which makes them go grey.

                  If you boil them in the water that you've been soaking them in, there really isn't anywhere for the vitamins to escape to....

                  1. My grandmother would regularly peel and cut up her potatoes early in the morning, long before the meal where they were needed, with spectacular (mashed) results. I have been speculating whether the results were due to my grandfather's strong arm or the long soak.

                    1. I made french fries a few weeks ago, I set my mandolin on top of a large bowl of cold water, so they went right in. It keeps them from going brown. I made sure to pat them dry before they went in the hot oil, though.

                      1. My grandmother used to peel and cut up her potatoes for Sunday dinner in the morning long before they needed to be cooked. They sat in water until they had potato shapes of starch floating on the top of the water. (Hard to describe many decades later.) Then they were boiled and my grandfather mashed the heck out of them. They were spectacular, and I've always wondered if it was the soaking or the arm of the masher, or both.

                        1. We'll do this before a big family gathering (like Christmas) - usually peeling and cutting up the spuds the night before. I'm sure that it ruins the nutrional content but, once or twice a year, who gives a flying one for nutrition.

                          1. I worked at a restaurant that did this all the time when making home made potato chips. Actually, we would soak the chips after slicing them for an hour or so, then drain them and put them back into a container of fresh water to store before frying them. As another poster mentioned, it was to draw out the excess starch. If we didn't do this, the chips would get too dark before they finished cooking.