How To Blanch Tomatoes & Onions

Regular readers will notice that a few recipes featured here call for ‘blanching’ of vegetables. Many of my dear readers have left comments asking ‘how to blanch onions and tomatoes’.

Blanching is partially cooking vegetables in boiling water for a short period and immediately plunging them in cold water to stop the cooking process. Blanching helps soften and preserve the colors of vegetables. Learn more on the basics of blanching.

For few recipes that involve greens and vegetables like cauliflower, french beans, lima beans, amaranth leaves, spinach, tomatoes and onions, I sometimes blanch and use them.

How to blanch tomatoes & onions?

Onions & Tomatoes ready for blanching

To blanch onions, peel the onions, make a cross at the root end. Bring salted water to a rolling boil in a large vessel and carefully drop the onions in the hot water. Continue to boil for 4-5 mts or till al dente. Turn off heat and immediately remove the blanched onions and place them in cold water. This process will stop the onions from overcooking. Drain from cold water once they cool completely and use as called for in the recipe.

blanched-tomatoes blanched-onions
Blanched Tomatoes ~ Blanched Onions

Follow the same procedure for tomatoes. Make a cross at the bottom end of the tomatoes and place them in a vessel of boiling water. Tomatoes require lesser time in boiling water as compared to onions. Let the tomatoes cook in boiling water for 2-3 mts. Immediately remove them and place in cold water and once they cool completely, drain the water and peel the tomatoes. You can chop or grind to a paste or as called for in the recipe.

Grinding the blanched onions yields boiled onion paste which works as a great base for dishes like Butter Paneer Masala. Grind the blanched and peeled tomatoes and your tomato puree is ready.

tomato-puree blanched-onion-paste
Tomato Puree ~ Boiled Onion Paste


To peel the skin of tomatoes easily, I boil the tomatoes for just a mt and then plunge into cold water. To prepare blanched tomato paste, I let the tomatoes cook in boiling water for at least 3 mts if they are firm and large and lesser time if they are soft and smaller in size. If I have time on hand, I de-seed the blanched tomatoes and puree!

How to articles:
How to make butter and ghee – photo tutorial
How to make rava dosa – photo tutorial
How to make ginger garlic paste

How To Blanch Tomatoes & Onions

  Prepare time:
 Serves: 2

 Main Ingredients:

  •  onions
  •   tomatoes


  • Cilantro

    Sailu, good to see you posting the basics of cooking. Blanching the tomatoes makes a huge difference in most gravies. These tips should be very useful to new cooks. Great job!!!

  • Kalyani

    Nice pictures with basics of cooking …. thanks for sharing the tips sailu ….

  • Vikas

    I think you had explained the blanching of tomatoes earlier as well. I had tried it and it works perfectly. Didn’t know Onions could also be blanched.

    Will try it, time permitting.

    How does blanching vegetables help? I mean are they cooked in the regular manner after blanching?

    In an earlier post you had explained how to store ginger garlic paste. For how long can tomato puree be stored? Should it be frozen or just kept in the ref?

    By blanching cauliflower or broccoli which are dense crisper vegetables, we cut down on the cooking time especially while preparing stir fries like Aloo Gobhi. When we add the blanched vegetables along with the less dense vegetables, everything will be cooked at the same time. So there is shorter cooking time with less absorption of oil. In the recipes featured here, blanched vegetables are cooked in the regular manner after blanching. I also sometimes blanch vegetables like carrot/cauliflower/french beans when I prepare salad.

    Tomato puree can be stored by freezing (placing in ice cube tray helps in easy removal) for a longer period. If placing in the fridge, use it within 3-4 days.

  • Shreya

    Hi Sailu, this is such a useful, informative post. I normally never blanch or make purees, and often peel tomatoes directly (the non-desi ones) and prepare onion paste also directly. I do hope there is nothing wrong in this. I would love to try and prepare this way…

  • josh

    Hi Sailu ji,
    Very informative “How to” series here. I enjoyed every post and tried most of the kids zone recipes these days..more about the trials at their respective posts.
    blanching keeps the colour and nutrients intact is that right?So when we make aanapakaya or beerakaya, if we add salt to them, the water content in them comes out and the curry becomes watery in just a couple mins. So should we put the lid on for these curries or evaporate the water.My husband argues, if we leave the lid and evaporate the water from these vegies, then there is nothing in the vegetable left which is nutritious.Then how can u prepare a berrakaya menthi podi or nuvvulapodi kura or anapakaya nuvvula koora by boiling( dry dishes)? should we blanch them as well??

  • Santhi

    Hi Sailu, the posts in the ‘How to’ series are very helpful. Thanks for sharing these tips. Could you please add a post in this series on how to prepare garam masala?

  • mohan

    hi sailuji,

    greetings of the day…found ur site very useful and certainly it is a gift for beginners and people(like me)who r away from family..thanks a lot for ur work..i tried one recipe and i became ur fan..whenever time permits i made it a habit to browse ur site and go thro the all the contents…thanks once again..


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  • vijay

    Hi Sailuji,

    Your cooking procedures and tips have been excellent to medium cooks like me. By the way will you please let me know how to make the typical Tamil “Gun Powder” to be eater with idlis. Also please let me know how to make idlis with Rice and dal instead of idli rava.


  • Lakshmi Jyothi

    There is a broken link on the first line of the page.

    • Anonymous

      Thanks for informing me.

    • Anonymous

      Thanks for informing me.

  • kalpana

    Hi, whenever we prepare gravy north indian dishes especially, we use cumin powder.
    Is it roasted cumin powder or raw powder that give good taste?
    pl reply

    • Sailu | Indian Food

      Roasted cumin powder

  • kalpana

    Hi, whenever we prepare gravy north indian dishes especially, we use cumin powder.
    Is it roasted cumin powder or raw powder that give good taste?
    pl reply

  • meena

    wow.. very good tip

  • Chupdiawaz

    How long can I keep tomato purée in refrigerator?

    • Sailu | Indian Food

      Freeze it.

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