Soaking potatoes before boiling and mashing them is a step that many experienced cooks swear by for making the creamiest, fluffiest mashed potatoes possible. There are a few reasons why soaking raw potatoes in water ahead of cooking can help you achieve mashed potato perfection.
1. Soaking removes excess starch
Potatoes contain a high amount of starch. This starch is responsible for potatoes’ characteristically starchy texture. While some starch is desirable in mashed potatoes to help bind the potatoes together, too much starch can make mashed potatoes gloopy and gluey. Soaking potatoes before boiling helps draw out some of their excess starch, resulting in a less gummy, more velvety mashed texture.
Here’s how it works: When potatoes are soaked in water, the starch granules in the potato cells absorb a lot of that water, causing them to swell up. As the starch granules swell, they are more easily released from the potato cells into the water. This leads to a significant amount of starch being leached out of the potatoes and into the soaking liquid. Leaching out some of this excess starch ahead of time gives you a headstart on getting smooth, creamy mashed texture.
2. Soaking makes potatoes easier to boil
Soaking potatoes before boiling also helps them cook more evenly and thoroughly. Dry, starchy potatoes can have a tendency to crack and break apart during boiling. Soaking makes the potatoes moist and pliable all the way through, which helps them hold together better during cooking. The added moisture goes a long way toward helping the potatoes cook evenly throughout.
Starting potatoes out soaked allows the boiling water to immediately penetrate deep into the potato flesh and begin turning the starch into gelatinized mush. Potatoes that go straight from dry into boiling water take longer for the insides to get fully penetrated and cooked through. Pre-soaking gets that process started early for more even cooking.
3. Soaking produces brighter, whiter potatoes
Another benefit of soaking potatoes before cooking them is that it can help preserve their natural white color. Potatoes contain an enzyme called polyphenol oxidase that causes browning when potatoes are exposed to air and water. Soaking whole unpeeled potatoes allows you to leach some of this enzyme out before the potatoes are boiled and mashed, resulting in a whiter mashed potato color.
Browning enzymes are most concentrated right under the potato skin, so peeling potatoes before soaking can maximize browning prevention even further. However, leaving the skins on while soaking makes it easier to peel off the skins later after cooking. The skins will slide right off soaked, cooked potatoes. The choice is yours!
4. Soaking breaks down cell structure
Finally, soaking raw potatoes in water leads to some breakdown of the cellular structure in the potato. This structural breakdown helps aid in the release of more starch and enzymes from the potatoes into the water. It allows the potatoes to cook into an ultrasmooth puree more easily later on.
The longer potatoes soak, the more the cell structures within them weaken as moisture penetrates deeper. Just 30 minutes to an hour is enough time for significant cellular breakdown to occur. Any soaking beyond that provides minimal additional benefit in most cases. Warm water accelerates the soaking process even more.
How long to soak potatoes before boiling
Most recipes recommend soaking cut, peeled potatoes for 30 minutes to 2 hours before boiling them to make mashed potatoes. However, even just 20-30 minutes of soaking time can make a noticeable difference compared to no soaking at all. The differences are most apparent in higher starch potato varieties like russets.
Soaking time can be increased for even starchier potatoes or decreased for lower starch potatoes like red potatoes or Yukon golds. Tiny new potatoes may only need 15 minutes of soaking since water penetrates them so quickly. Larger potatoes may benefit from slightly longer soak times up to 1 hour.
Soaking potatoes too long (over 2 hours) can lead to mushy, waterlogged boiled potatoes. Potatoes should never be soaked long enough for the edges to begin curling or deteriorating. 1-2 hours max is sufficient in most cases.
Soaking time guidelines
- New potatoes – 15 minutes
- Small potatoes (golf ball size) – 20-30 minutes
- Medium potatoes – 30-60 minutes
- Large potatoes – 1-2 hours
How to soak potatoes for the best mashed texture
Follow these steps for soaked mashed potato success:
- Wash and peel potatoes (optional). Cut into 1-2 inch chunks.
- Place cut potatoes in a bowl and cover with cold water by 2-3 inches.
- Let soak for desired time based on size.
- Drain potatoes well and rinse under running water.
- Boil potatoes until fork tender (about 10-15 minutes).
- Drain boiled potatoes well and mash with milk, butter, and seasonings as desired.
The potatoes are now ready to soak up all that good cream and butter for perfect mashes every time. The small extra step of soaking makes a big difference in getting the fluffiest, creamiest texture without glueiness.
Does soaking potatoes work for any mashed recipe?
Pre-soaking potatoes is ideal when making basic mashed potatoes to serve as a side dish. For most recipes for loaded mashed potatoes with lots of cheese, cream, eggs, or other rich mix-ins, soaking may not be necessary. The extra ingredients provide enough moisture and fat to create a smooth, creamy texture on their own. However, soaking certainly won’t hurt.
Other recipes where pre-soaking is recommended:
- Twice baked potatoes – Helps prevent a gummy texture
- Scalloped or au gratin potatoes – Allows creamier sauce permeation
- Gnocchi – For light, pillowy dumplings
- Potato pancakes and rostis – Leaches out starch for less sticking
In general, anytime you want mashed or boiled potatoes with an extra smooth consistency, consider giving them a quick soak first for the best results.
Frequently asked questions about soaking potatoes
Should potatoes be soaked in cold or warm water?
Either cold or room temperature water is effective for soaking. Warm or hot water can cause potatoes to get waterlogged or break down too much. The best soaking water temperature is between 40-70°F.
Is salt or vinegar added to the soaking water beneficial?
Adding salt, vinegar, or acid like lemon juice to the soaking water was once thought to help limit browning. However, research shows these ingredients don’t make a significant difference. Plain water works just fine.
Should potatoes be soaked immediately after peeling?
It’s best to soak potatoes fairly soon after cutting and peeling them to limit oxidation and browning. However, starting the soak immediately is not 100% necessary. Waiting 5-10 minutes before submerging them in water is fine.
Can potatoes be soaked too long?
Yes, potatoes left soaking overnight or for several hours can become waterlogged and begin deteriorating around the edges. They may fall apart during boiling. Limit soaking to 1-2 hours max for best results.
Do red or Yukon gold potatoes need soaking too?
Low starch potatoes like reds and Yukons can benefit from brief soaking, but don’t require as much time. Try just 15-30 minutes for them since they have less starch to leach out.
Should soaked potatoes be rinsed?
A quick rinse under running water after soaking and before boiling helps remove excess starch on the surface for even better results.
Conclusion
While not absolutely necessary, soaking potatoes before boiling them for mashed potatoes can make all the difference in achieving the fluffiest, creamiest mashed texture. Just 30 minutes to an hour of soaking allows excess starch to leach out of the potatoes, making them easier to cook evenly and mash smoothly. For most basic mashed potato recipes and other boiled potato dishes, advance soaking is an easy trick that can really level up your spuds.