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How to Fix Instant Pot Quick Release Spraying Starch

When I did the quick release I got a starchy spew with the steam that was released. Should I have let it rest a bit?

Short answer: Yes, you should let it rest a bit!

Longer answer:

I get the “quick release is spraying more than steam” question from time to time. It’s usually from my Macaroni and Cheese recipe – more on why that is in a minute – and most of the other times are from a bean recipe.

It happens to me too! Most of the time with these recipes, a quick release just releases steam. But, sometimes I get more than steam – the pressure cooker starts spitting and sputtering, and I get a mess – a fine mist of the food spraying out with the steam.

Q: What should I do when my Instant Pot quick release is spraying starch?

A: Carefully close the pressure release valve, let the pressure come down for five minutes, and try again. Carefully! The steam (and the spitting liquid) are pressure-boiling hot. Protect your hands with a towel or an oven mitt. When you try again after five minutes, the vent will spit a little bit – that’s normal, as it clears out the valve. But, if it keeps spraying stuff, repeat the process – close the valve, wait five more minutes, then try again.

It may take a few tries to get a clean pressure release. It depends on how hot the pot still is. If I’m impatient, I’ll keep trying to quick release every five minutes. If I have other things to do, I’ll give up, turn off the pot, and wait for the pressure to come down naturally.

Q: What’s going on? Is my pressure cooker malfunctioning?

A: No. This sometimes happens when you quick release a pressure cooker.

A couple of things could be happening when the valve is spraying more than steam:

  1. Releasing the pressure throws the liquid to a heavy boil. Pressure cooking works by increasing the boiling temperature in the pot. Under pressure, the water gets hotter before the boiling air can escape. Quick releasing the pressure reverses that process – the drop in pressure makes it easier for the air to escape, so the contents of the pot will spring to a boil. If the pot is full – right up against the max fill line – it may be close enough for the boiling to reach the vent.
  2. The contents of the pot are foaming. Foaming happens with starchy ingredients, like pasta, beans, grains, and potatoes. Starch mixes in with the liquid, and the boiling bubbles get stronger and less likely to pop. If you had a boil-over on a regular stove, you’ve seen this happen. The bubbles start foaming, stacking up on each other, and build up until they get too heavy and collapse on themselves…or they overflow the top of the pot. The same thing is happening inside the pressure cooker, but it is trapped inside by the sealed lid.

Spraying food is usually a combination of both – a sudden, heavy boil of starchy liquid. The result is a boil-over, like on a stove. But the boil-over can only escape through the pressure valve in a messy spray.

The workaround is the same as on a stovetop boil-over. Reduce the heat and the boil will come down. Unfortunately, we’re dealing with a sealed pot. It takes time to cool down before we can try again.

The other solution? Take preventative measures, and don’t have a boil-over in the first place. There are three ways to avoid it:

  1. Don’t quick release, let the pressure come down naturally. A natural pressure release will not boil over, because you never open the valve. (Also, you don’t have the vigorous boiling, which is easier on the food in the pot.) When I can, I go the natural pressure release route, but some recipes need the quick release to avoid overcooking.
  2. Don’t fill the pot more than 2/3rds full: The max fill line on pressure cookers is 2/3rds of the pot. The max fill gives the pot headroom – it has to have space to build up steam so it can build up pressure – but it is also there to keep boil-overs from happening. Don’t try to fit “a little bit more” into the cooker. (Note: I’m saying this as much for myself as for the readers. I always want to add a little too much water to my chicken broth recipe.)
  3. Don’t fill the pot more than 1/2 full when cooking starchy foods: Almost all pressure cookers have a max fill recommendation of 1/2 the pot for foamy foods like beans, peas, pasta, and other starches. The extra headroom helps keep the foaming away from the pressure release valve. (Note: I’m also not good at this one – but I’ll try to use rule #1 and not quick release when I’m cooking foamy foods.)

What do you think?

Questions? Other ideas? Leave them in the comments section below.

Related Posts

Instant Pot FAQ
How to fix Instant Pot Overheating
Instant Pot as a Slow Cooker?
My other Pressure Cooker Recipes

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3 Comments

  1. Razzy 7 says

    You’re right, it’s no fun to have the pressure cooker release that starchy, messy spray and as long as the food won’t overcook by waiting another 5 minutes to release the pressure, that’s what I do – WAIT.

    But sometimes I want to release the pressure immediately to avoid overcooking, so I throw a dish towel loosely over the lid, covering the vent as soon as I vent the pc. The dish towel probably will get messy but it’s no big deal.

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