This is where things get fiery. Never use waxy potatoes like Red Bliss, new potatoes, or fingerlings. They are the enemy of a good mash.
Waxy potatoes have too much moisture and too little starch. When you mash them, they turn into sticky, gluey paste. It’s like eating wallpaper glue—but less tasty.
Seriously, if you see a red-skinned potato in your pantry, roast it. Do not mash it. Save yourself the heartbreak.
A Fun Rule of Thumb
Think of potatoes like sponges. Russets are dry, thirsty sponges that want to soak up all your butter. Waxy potatoes are already wet sponges that reject anything delicious.
How To Boil A Potato For Mashed Potatoes
When in doubt, ask yourself: “Would this potato rather be a french fry or a salad potato?” If it’s fry material (Russets), it’s mash material. If it’s salad material (reds or fingerlings), keep it for that purpose.