Kitchen rescueRice, pasta and potatoesUsually saveable

How to fix lumpy mashed potato

Push the mash through a ricer or a sieve while it's still hot, then stir in warm milk and butter. Don't try to beat the lumps out with a food processor or electric whisk, as that turns mash gluey.

How you can tell

  • Firm lumps of potato in otherwise smooth mash
  • Hard or waxy bits that don't break down when you mash
  • An uneven, patchy texture

Why it happens

Lumps usually mean some of the potatoes weren't cooked all the way through, so the firm pieces won't mash down. This happens when potatoes are cut into uneven sizes, or drained before the largest pieces are tender. Mashing potatoes after they've cooled also makes lumps more likely, because cooled starch firms up. Beating hard to get rid of lumps releases too much starch and makes the mash sticky and gluey.

How to fix it

Option 1Rice or sieve it

  1. While the mash is hot, push it through a potato ricer or press it through a sieve with the back of a spoon
  2. Stir in warm milk and butter gently
  3. Season to taste

Option 2Cook the lumps a little more

  1. If the lumps are hard and clearly undercooked, pick them out
  2. Simmer them in a little water or milk until soft, then mash them and stir them back in

Next time

  • Cut potatoes into evenly sized pieces
  • Simmer them until a knife slides into the largest piece with no resistance
  • Drain well, let them steam dry briefly, then mash while hot
  • Use a ricer or masher, not a food processor or blender
General kitchen guidance, not food-safety advice. If food may be unsafe, for example undercooked meat or anything left out too long, follow the Food Standards Agency and throw it away if in doubt.