Stains in your Instant Pot stainless steel inner pot after the first water test? Usually caused by lime or minerals; safe and easy to clean.

Recognize this?

After the first “water test” (for example, boiling water for 5 minutes), you notice in the stainless steel (304) inner pot:

  • White spots or haze (lime/minerals)

  • Dark specks or rings on the bottom (minerals + heat)

  • Sometimes a rainbow-like sheen (heat tint/oxide layer)

This may look “burned in,” but in nearly all cases it’s purely cosmetic.

What causes these marks?

When heating, minerals in tap water (like calcium and magnesium) can precipitate directly onto stainless steel. The heat makes them adhere more strongly.
Important to know:

  • It’s not mold

  • It’s not harmful and not unsafe

  • It does not affect your Instant Pot’s performance

Solution 1 (most common): clean with white vinegar (2 minutes)

  1. Pour a thin layer of white vinegar into the inner pot (just enough to cover the bottom).

  2. Let it sit for 5 minutes.

  3. Rub with a soft sponge or microfiber cloth.

  4. Rinse thoroughly with warm water.

  5. Dry immediately (prevents new water stains).

Tip: For stubborn spots, repeat steps 1–3 or let the vinegar sit for 10 minutes.

Solution 2: citric acid (alternative for lime or haze)

  1. Dissolve 1 tablespoon of citric acid in warm water (enough to cover the bottom).

  2. Let it soak for 10 minutes.

  3. Wash, rinse well, and dry.

What NOT to do (to avoid damage)

  • No steel wool or metal scouring pads (scratches)

  • No chlorine/bleach (can corrode stainless steel)

  • Avoid harsh abrasives; use vinegar/citric acid and a soft sponge instead

How to prevent new stains

  • Use filtered water for tests or steaming if you have hard water

  • Rinse and dry the inner pot immediately after use

  • Don’t leave water standing in the pot for long periods

When is it actually a product issue?

In rare cases, there may be pitting (actual corrosion spots). Contact customer support for exchange or replacement if:

  • The spots barely improve after vinegar/citric acid, and/or

  • You can feel actual pits with your fingernail, or

  • You see rough holes that can’t be polished away

We’ll resolve it with a replacement or new inner pot.

Frequently Asked Questions

  • Are these stains dangerous when cooking?
    No. Mineral deposits and heat tint on stainless steel are cosmetic and safe.
  • Why does this happen after just one use with water?
    During the first heating, mineral buildup can appear instantly, especially with hard tap water.
  • Do I need to report this under warranty?
    Usually not. Only if there’s pitting or if it’s not removable with the steps above.
    If you think it’s necessary, you can request service or return here: www.kenners.nl/RMA