Blanching Vegetables – Why and How


What is “blanching”? When referring to cooking, this is a technique where you plunge cut-up vegetables in rapidly boiling water for a specific amount of time; they are then removed and placed in cold water (some say ice water) to quickly chill. What you do next depends on what you’re going to do with the veggies.


I like to blanch some vegetables before stir-frying, but here we are going to freeze a small harvest of broccoli from our greenhouse.

Why do we blanch vegetables before freezing? The most important reason is to stop enzymatic activity in the plant material which would eventually lead to decay. Freezing only slows down the enzymes, but blanching destroys the enzymes and also prevents changes in color, flavor and nutritive value. Fresh is best of course, but putting up food for the winter is a good thing too, and canned broccoli is not a quality product in any way, shape or form!

Fruit also contains enzymes (which is why some turn dark after cutting open) but the acid in the fruit helps preserve it without blanching.

Another reason for blanching is to clean the food surface of microorganisms and also to purge air from the plant tissue which could lead to oxidation.


One gallon of water will generally be enough to blanch 1lb. of veggies. Cut them uniformly so they all heat at the same rate. Do not add salt to the water. Find a basic good book such as So Easy to Preserve or go to your county extension website for more info on how long to blanch specific veggies

. IMG_3939


This broccoli was blanched for 3 minutes. I like to freeze on a lined baking sheet so the pieces don’t stick together and I can remove only what I want. Let freeze for about an hour or until firm, then place in freezer bags to store. Remember to label and date.



My Master Food Preserver literature says you can freeze small whole peppers such as jalapenos without blanching, and I have done this with success. I also like to char the skin off of poblanos and anaheims, cut them open and lay them flat on a baking sheet to freeze, then put them in freezer bags. I don’t think I need to tell you how to use those, do I?

National Center for Home Food Preservation

Broccoli by Brody