Zojirushi Blog

Design Explained –
Our Steam Vent Caps

Do you know that most of our rice cookers have a cap on the steam vent? Compared to conventional rice cookers, our advanced rice cookers – the ones that utilize a microcomputer – are sleeker, with tight-fitting components and lids. We make these rice cookers with steam venting systems that consists of three components – a vent, a vent cap, and a vent cap receptacle.

This is the Steam Vent Cap!

Each piece of the venting system has a purpose. The vent is a tube-like opening that goes through the cover and inner lid, into the body of the rice cooker where the inner pan rests. The vent is covered by the steam vent cap, which rests in the steam vent cap receptacle, keeping it securely on the cover of the rice cooker. The entire system is built to seamlessly blend into the top of the rice cookers. One customer even brought his appliance into our office inquiring about the system because he didn’t realize it was there!

Can you spot the Steam Vent Cap?

The steam venting system works in conjunction with good rice prep. The first step is to correctly measure the right amount of rice and water. Then, it’s important to wash the rice correctly, removing excess starch and bran or dust from the rice kernels. Once the rice begins cooking, the rice cooker releases excess steam through the vent, and the steam vent cap catches any foamy substances that come out with the steam. The rice cooks better this way because the steam vent cap allows the rice cooker to cook your rice at a higher heat, without worrying about overflow because the steam vent cap can capture excess moisture and bubbles that may foam up.

Yay for delicious rice!

As long as the vent cap is washed under running water and the steam vent cap receptacle area is wiped with a soft cloth to remove any moisture, the steam venting system in your Zojirushi advanced rice cooker should work wonderfully. Remember to remove and clean the inner lid and you’ll have perfectly cooked rice every time!

Don’t forget to remove and clean the Inner Lid!

Check out our full line up in the Products section, and be sure to comment with any questions you might have.

61 thoughts on “Design Explained –
Our Steam Vent Caps

  1. There is a lot of steam coming from the steam cap, really shoots up. And the rice was dry. It was a gift (slightly used) so I’m wondering if there is a missing gasket or if it is supposed to do this.

  2. Hi, cooking the green tea porridge from the manual for the first time and starchy liquid is pooling up and out of the steam cap and dripping down the outside of the cooker – what could be wrong?

    • Hi Lyn, starchy steam tends to be caused by the excess starch that may be left in the rice. We recommend that the rice be thoroughly rinsed, generally rinsing it 3 to 4 times will prevent this from occurring. Please let us know if you have any more questions!

    • Hi Daryl, the inner lid will help sealing the lid and regulate the release of steam during cooking. When using the Keep Warm feature, the inner lid will prevent the rice from drying out. For the best results and experience with the rice cookers it’s best to always use the rice cooker with the inner lid.
      Please let us know if you have any more questions!

  3. We’ve been using our NP-GBC05 extensively for cooking oatmeal. Though it does a great job, there is virtually always overflow beyond the vent and down the back of the cooker. Is this just the nature of steel cut oats or could it be mitigated by rinsing beforehand? I understand that the cooker wasn’t designed for exactly this purpose.

    • Hi Orlando, overflow can commonly occur if the water ratio is off or if the white rice setting is used.

      The maximum and minimum amount of Steel Cut Oatmeal you can cook in your unit is 1 cup uncooked oats with 2 1/2 cups of water (using the measuring cup provided). It also helps to rinse the steel cut oatmeal and the porridge setting should be used.
      Following the suggested grain to water ratio should help alleviate your issue.

      I hope this information helps.

      • Thanks for the info. I’ve tried numerous ratios, and always on the porridge setting. I think the issue might be that we only use half of the plastic cup size.
        I guess we don’t eat enough oats. : )

    • Hi Nou, excess steam escaping from the sides of the lid may be due to the following:
      1. There is something blocking the steam vent. Please take a look at the vent on the lid to make sure it is not blocked. Take a well wrung cloth and wipe the area down to ensure it is clear.
      2. The steam vent cap has residue. To resolve this, take off the steam vent cap and wash it with a soft sponge, rinse it and dry it off.
      3. The inner lid gasket is worn. If you have had the rice cooker for a while then it’s possible that the gasket that is either around the detachable inner lid or on the actual lid is wearing. If the gasket is on the inner lid then a replacement can be ordered here: https://www.zojirushi.com/app/spare_parts/category/rice-cookers
      If the gasket is on the actual lid then one of our authorized service centers can assist you with the replacement: https://www.zojirushi.com/app/service_centers

  4. If the inner lid went missing , would it affect the rice cooking process? What is the function of the inner lid? Please advise, thanks

  5. Hi, I’ve had the issue twice now of congee bubbling through inner lid and steam vent while cooking, once even out onto the top of the cooker I am following the rice/water levels as indicated on the side of the pot. Last time I made a full recipe, today a 3/4 recipe, i.e. I am not overfilling. It makes a mess that is hard to clean up. How do I prevent this from happening in future?

  6. What if I accidentally cooked the rice without the inner lid and I have the rice cooker that says “do not use without inner lid” written on the inside? Is the rice still safe to eat??

    • Hi there, for the best results and performance it’s best to ensure all parts are installed correctly. The high-quality materials we use for our products are carefully selected and tested and are completely safe for use with food and beverages. If the rice cooker is used without the inner lid then some overflow may be experienced and the rice may not be cooked evenly. I hope this helps!

  7. hello
    I am missing the reverse stopper valve – little pin with a head that goes on the steam vent.
    Is it necessary to cook rice?
    What is its purpose?
    thank you

  8. Hello
    have a NS-PC model.
    I am missing the reverse stopper valve – little pin with a head that goes on the steam vent.
    Is it necessary to cook rice?
    What is its purpose?
    thank you

    • Hi John, the steam vent cap assembly help regulate the release of steam while cooking rice or keeping it warm. If any part is missing it can affect the quality of the cooked rice or cause excess condensation to accumulate while the rice is in keep warm. We recommend that the complete assembly is used for the best possible results.

  9. Hi, my zojirushi outer lid won’t close because something is wrong with the spring inside. The white plastic piece is retracted so the lid keeps popping open on its own. I unscrewed the 2 screws on top and the 3 screws underneath but I am unable to remove any pieces. Can someone show to tell me how I can fix this? Right now I am taping the lid down when rice is cooking so it doesn’t pop open.
    Thank you!!
    Shirley L.

  10. I am looking for a replacement steam cap for my HBC10 model but looks to be out of stock. Will this ever come back in stock?

  11. Hi. I have a NP-NVC18 that is a year old. A few weeks ago it started making a shrill whistling noise about 2/3rds the way through the rice cycle. It comes and goes for 15 min or so. There is also more condensation on the sides of the lid near the back, by the hinges.

    I have cleaned everything, including the steam lid, everything is spotless!

    I am using the same jasmine rice I always use, usually 6 cups at a time.

    I have inspected the inner gasket, it does not seem damaged or worn at all, and it shouldn’t be given the rice maker is only a year old. We make rice in it about 2 times a week.


  12. Hello,

    I have just bought the NS-ZLH10.
    Can you tell me what is the inner lid made from? I mean which kind of metal? Is it aluminum or stainless steel?
    Many thanks,

    • Hi Ron, the NS-ZLH10 is not a Zojirushi America product, it is a foreign model. Unfortunately, we would be unable to provide you with information on this rice cooker. However, the inner lids for our rice cookers will be made of aluminum or stainless steel. We apologize for the inconvenience.

  13. I cleaned my rice cooker and inside the lid there’s a styrofoam or something that looks like a bubble wrap that looks burned from countless uses. I want to replace it however I don’t know where to find one and what’s that used for by the way. Understanding this may help find a temporary replacement while I look for the original part.

  14. Sometimes when I open the lid after 1-2 days of warming, excess water runs out of the inner lid when the lid is open/vertical – and it seems to cause the remaining rice to dry out prematurely. What can I do?

  15. Hi. On my NP-HCC18 Rice cooker, there’s always a lot of condensation on the inner lid several hours after turning off the cooker that I have to wipe it down so it doesn’t drip on the cooked rice. Shouldn’t the vent system prevent this much condensation?

    • Hi VC, when the rice cooker is on Keep Warm, then it will prevent excess condensation from being created. However, once the rice cooker is turn off, then as it cools the steam will turn into condensation since there is no heat source any longer. We recommend to always store the rice in the fridge or freezing it after the rice cooker is turned off. This will prevent the rice from yellowing or spoiling when the rice cooker is off. Hope this helps!

  16. Hi, we have a rice cooker that’s probably 15 to 20 years old and within the last few years it’s gotten too a point where it doesn’t keep the rice fresh very long anymore and we have to use more water than we originally had to use per cup of rice when cooking it. Is it just finally wore out or is there something? Or is there anything I can look for that may pinpoint the issue? Any help would be greatly appreciated!

  17. NP-HCC10 made 1 cup white rice without steam vent, forgot to put it back. everything seems ok and rice came out fine. is there anything to worry about?

    • Hi Vic, the steam vent cap helps catch any foamy steam that may come out if the rice is not washed properly and helps regulate the heat so the rice cooker is able to cook rice to perfection every time. Although, it’s not ideal to use the rice cooker without the steam vent cap, forgetting once won’t affect the rice cooker adversely. The cooked rice might not be cooked properly so we always recommend to replace it before starting to cook. Hope this helps!

  18. I have the NS-TSC10 and the rice comes out mushy when I use the correct amount of water. There is a mound of rice that is mushier than the rest, so it looks like water is dripping down where the mushier part is. What is wrong with my rice cooker?

    • Hi Allan, uneven cooking can be caused sometimes by dents in the pan or if the heating element has burnt bits on it. If the pan is dented then it will need to be replaced and if there are small burnt bits on the heating element, they can be sanded down with a very fine grit sand paper. If this is not the case, then the rice cooker will need inspection and testing by an authorized service center. Please reach out to our Customer Service team for additional assistance and they will be happy to troubleshoot the issue with you!

  19. I am considering buying one of your Micom rice cookers. I understand rice cookers are not supposed to be used next to a wall or under a cabinet, but I have a very small kitchen and have no choice. Will the steam vent keep steam from coming out of the cooker and protect my wall or will this be a problem?

    • Hi Cory, the steam vent will release steam when the rice cooker is cooking rice. If the cabinets are very close the to top of the rice cooker they can be warped or damaged by the steam. The steam vent will help release excess steam generated by the rice cooker and will capture any starchy foam that may come out during the cooking process. I hope this helps! Please let us know if you have any other questions!

  20. I have an HTC-18 and steam is coming out of the side of the rice cooker. It’s a pretty old unit (maybe 15 years old?) but works great other than the steam escaping the sides.

    I’m guessing it’s the removable inner lid seal. Is there a specific way to disassemble and thoroughly wash the part?

    I see that a replacement part is out of stock / discontinues everywhere else, so I’m guessing a thorough cleaning is my only option?

    • Hi Brady, it sounds like the inner lid is worn. The gasket on the inner lid makes a seal once the lid is closed but overtime the rubber will become less pliable and won’t make a good seal anymore. At this point, we would recommend replacing the inner lid. A cleaning will not resolve the issue. Furthermore, the inner lid is not a part that can be disassembled.

      Please reach out to our Customer Service Team, they can double check on our current stock or add you to a notification list to let you know when the part is back in stock: https://www.zojirushi.com/app/customer_service/entry

  21. The inner lid on our NP-NVC18 keeps cracking. We are on our 3rd inner lid and it seems that it keeps on cracking right on the same spot, the flat of the plastic part.

    At this point, I am having second thoughts about ordering a 4th one. We are afraid that it’ll keep on happening.

    We try to clean the inner lid at least every other cook. We are wondering if there is a defect with our machine or is there something we are doing wrong?

  22. When opening the lid after the rice is done cooking, water drips down from the inner lid. There is no blockage to steam vent. The rice seems to cook fine and does not dry out during warming but have to wipe water every time the lid is open.

    • Hi Tom, it is normal for some steam to condense on the lid and may drip a little when opening the lid. Now, if you have had your rice cooker for a while and have noticed and increase of dew, then this can be an indication that the inner lid gasket may be wearing. The rubber gasket makes a tight seal around the lid but over time and use it will wear and may allow some outside air to enter. When this happens, the colder outside air will create more dew to gather on the lid’s inner surface. If you need an inner lid replacement please visit: https://shop.zojirushi.com/pages/parts?type=parts-rice-cookers

      If the inner lid gasket is attached to the actual lid, then please reach out to our customer service team and they will be able to provide you with more information: https://www.zojirushi.com/app/customer_service/entry

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