Mashed potato

June 19, 2009 12:55 PM

Why does homemade mashed potato taste like fake mashed potato the day after?

Is there a way I can make a load of mashed potato and keep it for a few days without it tasting weird? It always tastes like that horrible powdered stuff when eaten a few days after. In fact, it seems potatoes of any description don't do so well as leftovers. Any tips to make them taste better?

posted by stenoboy to food & drink (17 comments total)

The starches are breaking down, and becoming like the broken-starch flakes.
posted by notsnot at 12:59 PM on June 19

My guess is it has something to do with moisture content. There are a couple of things I do with left-over mashed potatoes (on the rare occasions when there actually are some). If I want to have straight up mashed potatoes again, I will heat them over a double boiler with a little bit of water and some cream or sour cream.

Mashed potatoes also make really great potato cakes (like this recipe).

If I'm in a hurry or don't want to deal with the other two examples above, I've noticed that if I mix the mashed potatoes with left over gravy or some type of sauce and heat them up in the microwave they're really tasty. Heating up in the microwave without sauce can be horrific though.
posted by Kimberly at 1:02 PM on June 19 [1 favorite has favorites]

I don't know exactly why, but you should google resistant starch. Cooled potato starch becomes resistant....whatever that means.
posted by idle at 1:04 PM on June 19

Um. My mashed potatoes never taste like instant the next day. I can't imagine I make them much differently than anyone else.

I use medium sized red or yukon gold potatoes. Depending on my mood and the rest of the meal. Sometimes I peel the red ones all the way/sometimes I leave on half the peel/sometimes I don't peel at all. There's no reason to peel the gold potatoes. The skins are thin and mash up nicely. I only quarter the potatoes before boiling them. If I chop them up too small they cook too fast and I end up over cooking them.

I cook the potatoes in salted water until I can easily pierce them with a fork but they aren't yet at the crumbling stage. If you over cook them to the crumbling stage, you release too much starch and they get gluey.

I rinse the potatoes in coolish water to stop the cooking and also to rinse off the starchy stuff that gets released when you boil them.

Then they go back in the pot with too much real butter and a smidge of milk. I mash with a hand masher, not a mixer. I think an electric mixer releases too much starch and causes them to get gluey.

I season them up at this point. I like garlic, rosemary, salt and pepper. My mom only uses a seasoning (orange) salt and pepper. Sometimes I season them with dill if I've left on the redskins (yummy).

After they're all mashed (I vary the consistency based on the rustic-ness of the rest of the meal). I put them back on a very low burner and I add dollops of milk and stir occasionally while the rest of my meal finishes cooking.

How do you do it? If your issue is that the potatoes taste starchy or gluey the next day, my description above might help.
posted by dchrssyr at 1:08 PM on June 19 [2 favorites has favorites]

How are you reheating the leftovers? I find that baking them helps a lot, and they don't get gluey or liquidy like they do in the microwave.
posted by necessitas at 1:14 PM on June 19

Yeah, if you do a chunkier mash, they tend to stay better in the fridge for a couple days. Overcooking and mixing are the enemies here!
posted by shownomercy at 1:15 PM on June 19

"I use medium sized red or yukon gold potatoes."

The use of waxy rather than mealy (and starchier) potatoes may be why your mashed potatoes keep better.

I prefer to use russets with a yukon or two in there for texture. Also, I am careful not to overcook them before mashing. They need to have a little stiffness in them to mash well without turning into pudding.

Also, I quite like instant mashed potates. Sure, they are different from the scratch made but I think they are still yummy. Especially the ones they carry at Costco. Those are spectacular for instant.
posted by bz at 1:25 PM on June 19

Harold McGee covers this in his wonderful book On Food and Cooking:

Leftover potatoes often suffer from a stale, cardboard-like flavor that develops over several days in the refrigerator, but within a few hours if the potatoes are kept hot for prolonged service. It turns out that the aromatic fragments of membrane lipids are temporarily stabilized by the tuber's antioxidant vitamin C; but with the the vitamin C is used up and the fragments become oxidized to a series of less pleasant aldehydes".

I have a friend who likes to prepare potatoes the day before an event such as Thanksgiving dinner. She seems unable to detect the disagreeable flavor that this gives the potatoes. Not everyone is equally sensitive to it. For those who are, it's always better to make the other foods in advance, since their flavor suffers less than that of potatoes, and cook the potatoes not too long before the meal.

Instant mashed potatoes are much improved over what they were when I was a kid, and I think they're worth eating, but it's always obvious that they are not freshly prepared. The flavor is always a bit off.
posted by Ery at 2:11 PM on June 19 [2 favorites has favorites]

Sorry. In the Harold McGee quote, "with time the vitamin C is used up."
posted by Ery at 2:13 PM on June 19

I use Yukon Gold for my mashed potatoes, too, and the leftovers hold up very well. Maybe it might be as simple as switching brands?
posted by greenland at 2:32 PM on June 19

my mom used to take leftover mashed potatoes & mix in flour 'until the potatoes can't take any more.' she'd then lightly flour the surface of the cutting board, roll the potato/flour dough VERY thin, and put in the oven under the broiler for a small amount of time (like, 1 minute) until the dough would brown. flip, brown the other side. pull out of the oven, brush with melted butter, cut into squares, and eat. them's some good leftover potatoes.
posted by msconduct at 2:36 PM on June 19 [2 favorites has favorites]

Leftover mashed potatoes are so versatile - try
fishcakes
bubble and squeak
bubble & squeak cakes
cottage pie*
shepherds pie
or even lemon trickle mash cake.

When you want to just use up the potatoes, I'd second msconduct's method above or putting the mash in an oven proof dish with a good knob of butter on a low heat for about 20 minutes. A further five minutes with grated cheese and/or sliced tomatoes on top is good too.

* I know that parsnips are criminally ignored in most of the US, just substitute extra potatoes for the parsnips in that recipe if they don't appeal.
posted by ceri richard at 3:48 PM on June 19

I use leftover mashed potatoes as thickening base for cream of broccoli soup -- saute a bunch of green onions (you could use leeks, but I hate cramming them in the crisper), add a clove of garlic, choppped broccoli (reserving just a few tablespoons of very finely chopped florets for after pureeing), a bay leaf, some chicken stock and cook until the broccoli is soft.

Remove the bay leaf, add a pinch of nutmeg, throw it in a blender with a reasonable amount of mashed potatoes (not a ton or it'll get gluey), add the little florets salt and pepper, reheat, and serve with a spoonful of sour cream and a pat of butter on top.

(I'm really hungry.)
posted by A Terrible Llama at 4:05 PM on June 19

notsnot is correct. It has to do with the starch. It depends on the species of potato, and how much you mixed up the potatoes to begin with - if you're doing mashed potatoes with milk and butter and making them really really creamy, you're much more likely to have glue-like potatoes later on. Rinsing hot potatoes with glue also makes this worse. And NEVER mash them with a blender.
posted by Cygnet at 4:19 PM on June 19

D'oh! I meant to type "rinsing potatoes with hot water". Brain fart.
posted by Cygnet at 4:19 PM on June 19

ceri richard has it right. never use leftover mashed potatoes as mashed potatoes. I think that's the key to all forms of leftovers, actually, that you do something else with them to make it less like... eating old food.

Shepherd's pie is fantastic stuff. You don't need to use lamb (although it is great), just think of it as an easier pot pie, in that you don't have to fuss with a pie crust. A sample filling: bite sized chicken, chopped onions, red bell peppers, green beans, and mushrooms, mixed in with a can of cream o' mushroom, then cover with mashed potatoes. Cover the top of the potatoes with cheese, and bake.

For a little more texture, mix some corn into the mashed potatoes before you spread it as a topping. Or some carmelized onions. Just because you're reheating them doesn't mean you can't be fundamentally altering them.
posted by Ghidorah at 5:07 PM on June 19

I totally know the flavor you're talking about, but my mashed potatoes taste fine up to three days later (they are always gone by then). I make sure to use an old-fashion masher, and I leave 1/3 to 1/2 the skin on, so that they have more vitamin C, as Ery points out, this is helpful. Definitely milk and butter (if not cream), and usually garlic thrown in with the boiling water and mashed along with the potatoes.
posted by oneirodynia at 9:19 PM on June 19