Knowing how to blanch vegetables can save you a lot of time and effort as you prepare your food for preserving. These rules hold true whether you are canning, freezing, or dehydrating.
Why We Blanch Vegetables
The blanching process is used to scald vegetables in boiling water or steam for a specific amount of time. It stops enzyme actions which can cause a loss of flavor, color, and texture when the food is frozen or dehydrated.
Blanching helps to rid the surface of food from dirt and organisms, it brightens the color and helps retain vitamins. Some vegetables are highly fibrous and taking the time to blanch them wilts, or softens them, so they will dry faster or be easier to package for freezing.
Blanching time is crucial and varies with the vegetable and size. Under-blanching vegetables can stimulate their enzymes and is worse than no blanching.
When water blanching, be careful and use the recommended times. Overdoing the blanching time will cause loss of flavor, color, vitamins, and minerals, so you will essentially transfer all the nutrients from the food to the boiling water.
Always Blanch These Vegetables
These vegetables will always require blanching. You should only use vegetables that are in excellent condition. Once you’ve completed the blanching process food can be stored in the freezer or processed in a dehydrator.
- Carrots – sliced rounds
- Eggplant – large pieces
- Green beans
- Sweet Potatoes and Yams
- Winter Squash
Boiling Water Blanching
If you find blanching vegetables as distasteful as I do, consider creating a blanching station to make the process go a bit faster. Begin by making an assembly line from your stovetop to your sink.
- A large stockpot, deep enough to submerge the food
- A clean sink, large bowl, or plastic tub
- Several clean towels
- Cold water
- Ice (as many pounds of ice as you have vegetables)
- A slotted spoon for removing the vegetables from the pot.
- Bring a stockpot filled with water to a rolling boil.
- Fill your kitchen sink, a large bowl, or a tub insert with cold water and ice.
- Place a small batch of vegetables in the boiling water for the recommended time
- After the allotted time, promptly submerge the vegetable pieces in a cold water bath using the slotted spoon. Change water frequently or use cold running water or ice water. If ice is used, about one pound of ice for each pound of vegetable is needed. Cooling vegetables should take the same amount of time as blanching.
- Once the blanched vegetables are cooled, remove them from the ice water and place on a clean kitchen towel to pat dry. If you plant to dehydrate the food, remove as much water as possible. Leaving extra water on the food will extend the drying time.
- Process the food for drying on dehydrator trays
Heating in steam is an alternative to water bath blanching and is even recommended for a few vegetables. Try this method for broccoli, pumpkin, sweet potatoes, and winter squash, which will help them keep their texture better. Steam blanching is not quicker than boiling water blanching, in fact, takes about 1½ times longer to get the vegetables to the proper state.
To steam blanch, use any pot with a tight lid that has a basket that will hold the food at least one inch above the boiling water in the pot. It only takes an inch or two of water in the pot to make steam. Bring the water to a boil and monitor it after each batch to make sure your pot does not go dry.
Put the vegetables in the basket in a single layer so that steam reaches all parts quickly. Cover the pot and keep the heat high. Start counting steaming time as soon as the lid is on. Try one of these kitchen hack alternatives if you do not have a steamer basket.
See this article from NCHFP for recommended blanching times for many common vegetables.
Microwave blanching may not be effective since research shows that some enzymes may not be inactivated. This could result in off-flavors and loss of texture and color with the finished product. [source] On the other hand, there seems to be some vitamin retention when using this method [source], since microwaving does not completely submerge the food into boiling water which can remove part of the nutrients.
If you want to try the microwave blanching method, be sure to work in small batches and use the directions for your specific microwave oven. Microwave blanching will not save your time or use less energy.
Use these blanching directions from GE Appliances to get started with microwave blanching.