The Science: Starchy vs. Waxy
The chief difference between potato types is the amount and nature of the starch they contain. This simple biological trait dictates how the potato reacts to heat and water.
- Baking potatoes contain amylose starch. This makes them fluffy when cooked but prone to falling apart in water.
- Boiling potatoes contain amylopectin. This acts similarly to pectin in fruit jams, helping the potato hold its structure even when boiled in soups or stews.
Baking Potatoes (Starchy)
These are often referred to as starchy potatoes. They typically have a long shape with coarse, cork-like skin. Inside, the texture is high in starch, dry, and mealy. While raw, they might feel firm, but they transform when cooked.
Best uses:
- Baking: They turn light and fluffy in the oven.
- Mashing: They break down easily into a light, creamy texture.
- Frying: Because of the low moisture and high starch, these are practically the only potatoes worth frying for crisp results.
Common varieties:
- Russet (Burbank, Arcadia, Norgold)
- Idaho (this is usually a Russet grown in Idaho)
- Long White (White Rose, California Long White)
Boiling Potatoes (Waxy)
These varieties are known as waxy potatoes. They can be round or long, but they almost always feature thin, smooth skin and flesh with a waxy feel. They are relatively high in moisture and sugar but low in starch.
Best uses:
- Salads and Soups: Their tendency to hold their shape makes them ideal for potato salad or chunky soups where you do not want the potato to dissolve.
- Roasting: They roast well without falling apart.
- Casseroles: They maintain integrity during long baking times in sauces.
Note on mashing: You can mash these, but the result will usually be thick and lumpy rather than fluffy. Overworking them can also lead to a gluey texture.
Common varieties:
- Red Potato (Red Bliss, Red Pontiac, La Soda)
- Yellow Potato (Yellow Finnish)
- Round White
- Salad Potato
All-Purpose Potatoes
There is a middle ground between the starchy and waxy categories. All-purpose potatoes have a medium starch content. They are moister than baking potatoes but will still hold together in boiling water better than a Russet.
Best uses:
- Roasting and Pan Frying: These are particularly well-suited for crisping up in a pan or oven.
- Gratins: They hold their shape in layers.
- Soups and Stews: They offer a good balance of texture.
They are versatile enough to be mashed or baked, though they will not produce the same ultra-fluffy results as a true starchy potato.
Common varieties:
- Yukon Gold
- Kennebec
- Katahdin
- Peruvian Blue
- Superior
What Are New Potatoes?
You may often see bags labeled simply as “new potatoes.” This is not a specific botanical variety. A new potato is simply an immature, small potato of any variety that has been harvested early. While red potatoes are frequently sold this way, a red potato is not automatically a new potato, nor is a new potato always red. Because they are young, they tend to be sweeter and hold their shape well, similar to waxy potatoes.
FAQ
Why are my mashed potatoes gummy or gluey?
This often happens when using waxy (boiling) potatoes for mashing. Their high moisture and low starch content can turn gluey if overworked. For light, fluffy mashed potatoes, it is usually better to use starchy potatoes like Russets.
Can I use Russet potatoes for potato salad?
It is not recommended. Russets are high in starch and tend to crumble and fall apart when boiled and tossed. For a salad where you want distinct cubes or slices, waxy varieties like Red Bliss or Yellow potatoes are a better choice.
Are Idaho potatoes a specific breed?
No. “Idaho” refers to the location where the potato was grown, not the variety. However, the vast majority of potatoes grown in Idaho are Russets, which is why the names are often used interchangeably in grocery stores.