When I microwave frozen spinach or amaranth greens to cook them, they sometimes get tough and fibrous. There doesn't seem to be a consistent pattern in when this happens, so I can't figure out how to avoid it.

So I ask you: why do frozen greens get tough and fibrous when cooked in the microwave, and how can I avoid it?

  • Are you sure that they get tough? Tough, fibrous veggies have lots of celulose. I don't see how your microwave can create additional celulose. I'd say that you either have batches of different quality, something consisting of older, fibrous plants, or sometimes undercook them (even with the same setting, depth of heaping or different plant water content can lead to different cooking times needed).
    – rumtscho
    Jul 3, 2011 at 23:49
  • While I'm not certain that it's not from variation in the quality of the product, frozen vegetables are usually quite consistent. I've never seen problems when heating in any other way. Obviously it's not creating new cellulose, but something in the process must be drying it out / toughening it up or causing other components to become tough. Anyone have specific ideas?
    – BobMcGee
    Jul 4, 2011 at 19:14

1 Answer 1


Microwave ovens cook primarily by spinning water molecules. Frozen water is less susceptible to this affect. I would guess that with certain vegetables, as frozen water turns to a liquid, it is quickly heated to the point that it boils and evaporates. The heating is less even than cooking frozen vegetables in a pot and leads to areas that are somewhat dehydrated and fibrous.

Try cooking your frozen vegetables in a container with a lose cover and additional water. This will allow them to cook or steam from the the outside in much like in a pot.


  • This makes perfect sense, and certainly explains why the texture is so unique and uniquely vile.
    – BobMcGee
    Jul 5, 2011 at 17:05

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