Freezing Vegetables

veggiesSummer has finally arrived and with it the farmer’s markets are exploding with the best of the season’s produce: kale, chard and other leafy greens have been around for months, but now we have sweet corn, green beans, zucchini, pattypan and other summer squashes, broccoli, cauliflower and even a few tomatoes.  While canning, pickling and root cellaring are all good options for many vegetables, some are best stored frozen, and if you have the space, this is the time to stock up on peak-season, fresh from the farm vegetables and store them away for the dark days of winter.  Although I will not stoop to mention the “e” word, stocking up now makes sense financially as well, as most vegetables are at their cheapest in the peak of the season.

Freezing summer vegetables is definitely the easiest and most convenient form of preserving; in some cases, it can be as simple as throwing a bag of green beans, or a couple of bell peppers, into the freezer whole, as you make the mad dash out the door for a weekend in the mountains.  But, a minor time investment now will ensure that your veggies stay at their peak of perfection and are easy and convenient to use when you want them this winter.  Read on for the details on how best to freeze the bounty of summer!

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Freezing Vegetables

All vegetables and fruit contain enzymes that hasten the ripening process; freezing produce will slow this enzymatic action (the high acid content of fruits slows the process even further) but will not stop the process completely. This is why if you simply toss a bag of uncooked spinach into the freezer, in three months it will be blackened and somewhat slimy, despite still being frozen – the enzymatic activity has continued in breaking down the produce, it has simply continued at a much-reduced rate.  Because of these enzymes, most vegetables require a short period of cooking prior to freezing in order to inactivate the enzymatic action.  This is typically called “blanch & shock” and consists of scalding fresh vegetables in boiling water, or in some cases, steam, and then plunging them into an ice-water bath in order to stop the cooking.  The blanch-and-shock method not only stops the enzymatic degradation of to-be-frozen vegetables, it creates a brilliant color, wilts certain leafy vegetables making them much more space-efficient, and is convenient for certain vegetables, like corn, that you may want to freeze fully cooked.

BLANCH & SHOCK

There is a good basic set of instructions, as well as blanching times for various vegetables, on the National Center for Home Food Preservation’s website.  The basics are simple and similar for any vegetable you wish to store frozen (hot & sweet peppers being a notable exception – they do not require a blanch). 

  1. Wash and prepare your fresh vegetables. I like to prepare veggies so that they are most convenient for their anticipated use; this includes trimming the stem ends off of kale, cutting the ends off of green beans and trimming to 2-inch lengths, chopping broccoli into florets.  While sometimes I am pressed for time (or simply lazy) and will stick a full Ziplock of jalapenos, unadulterated, in the freezer, it makes life much easier down the road when you come to using your frozen vegetables if you put in the time now.
  2. Boil a big pot of water.  Fill a large stockpot with water and bring to a boil, covered, over high heat.  You should have approximately one gallon of water per pound of prepared veggies.
  3. Prepare an ice bath.  Fill a large bowl with cold water and ice; use plenty of ice (about 1/3 ice to water works well for me) as it will melt with the heat of the par-cooked vegetables.  Keep this near the stove so that it is easy to quickly plunge the vegetables into the ice bath once blanching is complete.
  4. Blanch veggies. Drop your prepared veggies into rapidly boiling water (a basket makes this much easier for beans, broccoli, etc., but I find tongs are easier for leafy greens).  Put the cover back on the lid until the water returns to a boil.  Boil for 2-5 minutes (times are specified for common vegetables below) or until the vegetables turn a very bright green and are still tender-crisp.beans
  5. Shock.  Immediately plunge the blanched vegetables into the ice bath, and push well down into the water with tongs.  Allow to rest in the ice bath until completely chilled, about 5 minutes.
  6. Dry. Spread chilled vegetables on clean kitchen towels to dry; press another clean kitchen towel over the top of the veggies in order to soak up excess water before freezing.
  7. Freeze.  Fill Ziploc bags, Tupperware or other freezable containers with your produce.  Squeeze as much air as possible out of bags or containers; double-bagging will delay the onset of freezer burn.  Label each container with the vegetable, the date, and cooking time (par-cooked or fully cooked).
  • Asparagus: Wash, trim ends, cut into 2 to 3-inch lengths. Boil 2-3 minutes and to a bright green color.
  • Beans, Green, Snap and Wax: Wash, trim ends, cut into 2 to 3-inch lengths. Boil 3 minutes and to a bright green color.
  • Broccoli: Wash and cut into 1 to 2-inch florets. Boil 2-3 minutes and to a bright green color.
  • Brussel Sprouts: Wash and remove any yellowing leaves. Boil 3-5 minutes and to a bright green color.
  • Cauliflower: Wash and trim into 1 to 2-inch florets. Boil 3 minutes.
  • Corn, on the cob: Shuck and snap off large stem ends.  Boil corn on the cob for 7 – 12 minutes, or until fully cooked and kernels are tender.  Chill in an ice bath then cut kernels from the cob with a sharp knife.
  • Eggplant: Wash, trim ends, and slice into rounds or large julienne.  Boil for 3 – 4 minutes.
  • Greens, leafy (kale, collards, chard, arugula, spinach, bok choi, etc.): Wash and trim off tough stems. Boil 2-3 minutes and until a very bright green.
  • Herbs (leafy herbs like basil, sage, parsley, cilantro): Wash and keep leaves on the stems.  Swirl the stems in boiling water for about 1 minute, until leaves turn bright green and are wilted.  Plunge into ice bath; then dry.  At this point, herbs can be frozen on the stem, or leaves can be removed, chopped, and frozen in ice cube trays for ease of use.  A small amount of olive oil over the top of each ice cube will keep the herb-cube in cohorent form and aid in the prevention of freezer burn.
  • Okra: Wash, trim and boil for 3-4 minutes and a bright green.
  • Peas, in the pod or shelled: Wash, trim ends and peel strings, or shuck peas from the pod.  Boil for 2-3 minutes and a brilliant green.
  • Peppers, hot: Peppers do not need a blanch & shock. I often freeze small hot peppers (jalapenos, habaneros) whole, that way I can use the seeds or not as I wish.  However, it is convenient to have a certain amount of peppers trimmed, seeded and minced, and packed into teaspoon-full balls. I freeze these little balls of minced pepper individually, on a baking sheet, then once frozen I pile them into a Ziploc.
  • Peppers, sweet or Bell: Wash, trim seeds and ribs, and dice into 1-inch squares, rings or long strips.  Freeze.
  • Soybeans, green (edamame): Wash and boil for 5 minutes until bright green.
  • Squash, summer (zucchini, pattypan, crookneck, etc.): I don’t blanch & shock summer squash as I always freeze it grated, for use in quick breads; my theory is that the water released upon grating protects the vegetables from enzymatic degradation.  To freeze this way, wash summer squash, halve it and remove seeds.  Grate, with skin, through the large holes of a box grater and freeze in 1- or 2-cup portions (I freeze about 2 cups, or 1/2 pound, portions as that suits my recipes). To freeze summer squash for stir-fry, saute or other uses, wash, trim and seed the squash, then cut into large julienne or rounds.  Blanch in boiling water for 3 minutes.
  • Squash, winter (pumpkin, butternut, kabocha, etc.):  I don’t always freeze winter squash, as it will last for months on a cool (55 degrees is ideal; my kitchen runs about 65 degrees in winter) windowsill or counter. A wipe with olive oil over the skin of a pumpkin or squash will protect the squash from bacterial attack.  If I do freeze, it is often when I only need half of a particular squash for a recipe; thereupon I will peel & seed the squash, then dice the flesh into approximately 1-inch chunks. I freeze these separately, on a baking sheet (like IQF for berries) until solid then pack into a Ziploc bag. You can also prepare a puree of roasted or boiled winter squash and freeze the puree in 1- or 2-cup containers.  Squash does not require a blanch-and-shock.

I’ll add more vegetables as I freeze them.  I have heard that some people freeze whole tomatoes (who has that much freezer space?) but I have never done so. If you have a specific question or suggestion, feel free to leave it in the comments.

STORE

Vegetables preserved in this way should last 6 months to a year.  I try to use mine within about 8 months, which takes me from August, or peak produce time, to about April, when the first spring veggies are showing up at farmer’s markets.  Double-bagging will certainly help in preventing freezer burn as will keeping enough space in your freezer for air to circulate.

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5 comments

  1. Monica

    I am so happy to have stumbled upon this awesome resource! (And of course disappointed that I did not find this sooner!)

    I just wanted to let you know someone is reading this – I hope you’ll update it. I noticed in another post that you had frozen cubed pumpkin and I am curious to know how to do that.

    I will get started right away on freezing some of my CSA share!

  2. Monica

    Thank you! Especially for the tip about the olive oil to preserve the squash. That will come in handy as I am getting 8 winter squash + sometimes 1 pumpkin every week from my CSA. Great tip to freeze the part you don’t use too. I have water coming to a boil right now to get started on some eggplant rounds!

  3. Pingback: What A Pickle!

  4. MW

    I have been freezing tomatoes with great success. I found that making puree, sauce etc was too timing consuming. I throw the whole tomatoes in large ziplock bags. Come winter, making soups or especially chilis, I toss the entire tomatoes into the pot, rather than using canned tomatoes or fresh out of season. Works great. I don’t mind a few skins in a chili, but one could also peel tomatoes first before freezing if skins annoy.
    Now, who’s got some good recipes for frozen green beans? They end up too soggy for my go-to green been recipes……

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