Can you freeze mashed potatoes? Make them ahead

How far ahead can you make mashed potatoes?

Up to 3 to 4 days in the fridge, or weeks ahead in the freezer. The fridge number is the USDA's limit for cooked leftovers at 40°F (4°C) or below, from its leftovers guidance, and it counts from the day you cook them.

For Thanksgiving on Thursday, November 26, potatoes made on Monday evening are still inside the window on Thursday afternoon, but only just. The clock keeps running after dinner, and reheating doesn't reset it, so Monday's mash and everything left over from it has to be eaten by Friday. Make them Tuesday or Wednesday and the leftovers get the weekend.

If the week before is already full, make them in early November and freeze them. A batch that goes into the freezer three weeks out is one fewer pot on the day, and the reheating is the same job either way.

Can you freeze mashed potatoes, and how?

Yes, and buttery mash freezes better than most cooked potato. When a cooked potato freezes, its water separates from the starch, which is why frozen boiled or roast potatoes thaw out watery. Penn State Extension notes that butter, cream, sour cream or cream cheese in mashed potatoes gives them fat that helps them keep their texture in the freezer. America's Test Kitchen makes a second point in their freezing method: mashing has already broken the potatoes' cells, so the freezer has little left to damage.

1. Make the mash with its full share of butter and any cream, sour cream or cream cheese. Hold back about a quarter of the milk.
2. Cool it fast. Spread it in a shallow container or on a sheet pan and get it into the fridge within 2 hours of cooking. The USDA says hot food can go straight into the fridge, and a wide, shallow layer gets cold in the middle much faster than a deep bowl.
3. Portion it. Freeze 1-cup scoops on a parchment-lined sheet pan, then move them to a zip-top bag once they're hard (ATK's method), or press the mash flat in freezer bags with the air squeezed out.
4. Label each bag with the date and how many cups are in it.

Russets and Yukon Golds both work. ATK's point is that these moderate- to high-starch potatoes don't weep much once thawed.

Use frozen mash within about a month if you care about texture. Penn State's advice for cooked potato dishes is a few weeks. The USDA gives 3 to 4 months as the quality limit for frozen leftovers and says food kept at 0°F (−18°C) stays safe indefinitely, so a bag found in February is safe and simply less creamy.

Should you add the milk and butter before or after freezing?

Put the fat in before freezing and some of the liquid after. Penn State Extension credits the fat with keeping frozen mash's texture, so the butter and cream belong in the mash from the start. Milk is mostly water, and water is what separates out when the mash freezes and thaws.

The held-back milk has a second job. Mash straight from the fridge or freezer is stiff, and starch that freezes slowly can retrograde and turn a little gritty. ATK notes that thorough reheating reverses it, and the butter already in the mash smooths out what's left. A few tablespoons of hot milk stirred in at the end bring a reheated batch back to spoonable, and adding them then lets you judge the amount by eye. A batch frozen with all its milk often reheats looser than you want, and you can't take liquid back out.

Warm the milk first. Cold milk stirred into hot potatoes cools them below the 165°F you just reached, which means more heating and more stirring.

How to reheat mashed potatoes without making them gluey

Reheat them gently, stir with a spoon or spatula, and keep the hand mixer and blender away. Gluey mashed potatoes come from working cooked potato too hard, which breaks more of its cells and releases loose starch, and cold mash tempts people to beat it smooth. Heat and a little hot milk do that job instead.

Every method ends at the same place: 165°F (74°C) in the middle, checked with an instant-read thermometer, as the USDA's leftovers guidance asks for any reheated leftover.

• The microwave is best for a portion or two. ATK reheats a 1-cup portion covered, at 50 percent power for about 5 minutes, stirring now and then. Half power warms the middle before the edges dry out.
• The stovetop suits a big batch: a heavy pot over low heat with a splash of milk in the bottom, stirred and scraped every couple of minutes so the bottom doesn't scorch. Add butter and the rest of the hot milk once it's warm through.
• The oven is the one to use when the burners are taken. Penn State Extension reheats larger portions at 350°F (177°C) until the center reaches 165°F. Spread the mash in a buttered baking dish, dot the top with butter and cover it with foil so the surface doesn't dry out. A deep dish from the fridge takes a long time, so start it before the turkey comes out to rest.

Frozen mash can go straight into the microwave or pot without thawing, as the USDA allows for frozen leftovers. It takes longer, and the outside heats long before the frozen core. For a big batch, thaw it overnight in the fridge first, one of the USDA's safe thawing methods and the only one that doesn't need the food cooked right away. A slightly watery look after thawing is the separated water from the freezer, and it stirs back in as the mash heats.

Can you reheat mashed potatoes in a slow cooker?

Not from cold. The USDA advises against reheating leftovers in a slow cooker, and Clemson Cooperative Extension gives the same advice. A slow cooker warms a crock of fridge-cold potatoes so slowly that they spend hours between 40°F and 140°F (4°C and 60°C), the range the USDA calls the danger zone.

The slow cooker still earns its place on the day as a holding pot. Reheat the potatoes to 165°F on the stove or in the microwave, then move them into a slow cooker you've already preheated, and keep them at 140°F (60°C) or above until serving. Clemson's wording is to heat the food to steaming (165°F or above) before it goes into the preheated cooker (140°F or above). That frees the stove for the gravy.

Fitting make-ahead mash into the holiday week

Write down which day each dish is made, not only what's on the menu. Mashed potatoes, stuffing and cranberry sauce can all move off Thursday, and the Thanksgiving cooking timeline puts each one on its day. To size the batch, how much turkey per person also covers how much mash to make for a crowd.

In Hedgehog Chef's meal planner, put the mashed potatoes on the day you'll make them and the dinner on Thursday. A “Thaw it tonight” reminder arrives the evening before for planned recipes with frozen ingredients. If the mash goes into the freezer, the pantry keeps a freezer location with dates on each item, so the bag doesn't stay there until spring. Your usual recipe serves four and you have eleven coming: the free recipe scaler multiplies the ingredient list.