Importance of Blanching

It was the winter of 2014 in the Windy City of Chicago. One budding chef had just started his not so glamorous journey towards becoming a professional. 12-hour classes and 2 part-time jobs later, he was able to save up enough money to buy his first ever cookbook.

Now, you might be thinking why I have chosen to start off with this off-topic introduction and what connection the struggles of an amateur chef (myself)  have anything to do with blanching. The cookbook aforementioned was one of the best in the world. It was none other than The French Laundry Cookbook. One of the reasons why this book holds such a special place in my heart is the importance it gives to the basics of cooking. Chef Thomas Keller has a whole chapter on “big pot blanching” and you’ll learn a little bit about it if you read along.

The concept of blanching, if you haven’t encountered it before, is to partially cook vegetables in salted and boiling water. However, it is not so simple. In Chef Keller’s words, a cook that cannot blanch vegetables right, should probably look for another occupation. We’ll be looking at some of the basic principles of blanching through this short read, so start taking notes!

Let’s start with the first thing you would do if you were blanching vegetables and that starts with the pot. The French Laundry’s big pot blanching technique refers to having a slightly oversized pot of water to begin with. This helps the vegetables to move around freely in the boiling water and cook evenly.

The most basic, yet the most important aspect of blanching is the water. Fill up your “big pot” with clean water and set it on a high flame. We are looking to achieve a really intense and rolling boil. The movement in the water should mimic the white-water rapids of the mighty Ganges.

The next step is salt. In any type of cooking, this is where extraordinary chefs stand out from the average. Don’t be afraid to use salt. Generously salt the boiling water (a good ratio would be 15 g per liter of water) as blanching is an indirect way of seasoning the vegetables. Salting your blanching water heavily will not only season the vegetables but will also highlight the natural complexities of flavour that are present in the vegetable itself. Salt will bring out the natural sweetness in vegetables like carrots and green peas. In bitter leafy greens, it will balance the bitterness and make them more palatable in flavour and texture. Seasoning vegetables through blanching is different than just adding salt onto the vegetables as we rely heavily on a scientific concept called osmosis. I’m sure you might have encountered this concept in 8th grade biology but simply put, osmosis is the process through which a highly alkaline substance (our highly salted water) travels through the cell walls to reach the areas of low alkalinity (the inside of our vegetables).

Once we have seasoned the water, it is time to add the vegetables. But, before we hastily add our vegetables into the boiling water, let’s think one step ahead and set ourselves for success by setting up what is called an “ice bath”. Equal parts of water and ice in a bowl will suffice. If you have started cooking a lot, make this step a thumb rule for your future endeavours as the fine line between a perfectly blanched vegetable and mushy baby food could lie in the 10 seconds that you would spend hastily running around your kitchen trying to make an ice bath.

Now, the cooking time required for each vegetable is considerably subjective. It all depends on the type of vegetable, how it has been cut and the personal preference of how you want your vegetables cooked. Here is a typical guideline for cooking times of different vegetables:

If you have reached your desired texture on the vegetables, immediately strain them out and transfer them directly into the ice bath. The ice bath is one of the most important steps in blanching as it does two things. It immediately stops the vegetables from cooking any further (also known as “shocking”) and it also sets the bright colors of the vegetables by setting the various pigments in them (chlorophyll in green vegetables, carotene in orange and yellow vegetables). Do not let the vegetables sit in the ice bath for too long as this will result in a soggy product.