Fluid Dynamics and Coriander

Extending shelf life of greens .. Some kiddo physics conversation in the kitchen..

Sujatha Ratnala
3 min readMay 17, 2020

With the covid-19 and washing of veggies.. the corriander leaves began to rot. I came with an alternative plan of extending the greens.. Seperate the stems, seperate the upper half and cut them small.. Divide and conquer.. My younger one was around and I decided to have a fun chat with him.. And some made up conversations in this post..

What’s going on Mama?

What do you observe dear?

Well you have seperated the stems and the leaves..

I was having a hard time storing the washed greens.. It ended rotting after a few days.. and we are not grocery shopping for another 2 weeks. I think this method will solve it.. I have washed and dried the leaves.. And then seperated them into stems and greens. Can you squeeze the stem and feel it?

Oh there is so much water in it.

Yes.. The stem is so juicy and full of water.

You cut it into so many small parts.. There will be more exits. So more leakage?

Nice observation.. Think of them as pipes.. Since they are smaller pipes, they carry less water.. And the exits are in different places.. For this purpose, we have a cotton cloth to collect the drips. No more liquid mess.. All solids..

This is a convenient idea.. But think of the Cons..

The water draining out?

Yes.. And some nutrition is lost in the juices.. and the leaves getting oxidised.. It is best to consume veggies soon.. They are fresh in the plant.

Why are they fresh in the plant?

When the plant is rooted.. There is sunlight and air around.. There is movement of respiration and photosynthesis.. The plants have a protective covering.. and hence very fresh.. The moment we cut them.. these forces cease to exist.. And the water starts to ooze..

May be you can guess this.. People are saving the veggies in the freezer so that it lasts a long time.. How do you think freezing helps?

It freezes the liquids?

I too think so.. Some solid state physics.. During the fall time.. Do you know why the leaves fall?

You mean the fall leaves are related to water?

I think so.. The weather is cold and the trees and leaves full of moisture.. They cannot take it any more and hence fall off from the tree..

Right now my experiment serves my purpose.. stems for rasam, bigger leaves for Sambar and smaller ones for garnishing.. May be another time another approach..

Recently, I saw a video.. All the greens were washed and packed in cotton towels. It was spinned in a washning machine. The leaves look so puffed up and fresh and apparently last one month.. Kitchen and necessity are great innovation hubs and drive for sure..

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Sujatha Ratnala

I write.. I weave.. I walk.. कवयामि.. वयामि.. यामि.. Musings on Patterns, Science, Linguistics, Sanskrit et al..