Saturday, October 31, 2009

"How To" Make an Herb Oil Puree for the Freezer

Use this simple method to create deliciously potent herb oil puree for you freezer. I have used this method for a number of years since I learned that basil, cilantro, mint and other delicate herbs tend to lose flavour when froze on their own. The herb oil puree freezes a bit “soft” due to the high oil content. 

The herb oil purees are versatile and can be used in casseroles, sauces and soups and on bread and baguette. The photo above shows a basil and olive oil combination.  I add the garlic, nuts and cheese later when I want to make a fresh tasting  pesto. Once defrosted, you can lightly toast bread under the broiler and then top with the herb oil puree and lightly toast again.  Sprinkle with some chopped fresh garlic and tomato and broil a bit longer.  Spoon out for use in your favourite recipes.  You will have a fresher flavour if you toss the herb oil puree into pasta or swirl into soup at the end of cooking.  You can also use the puree when you sautee garlic and onions for recipes.

I use my own garden grown herbs or organic herbs that don't have added pesticides.  This recipe comes a bit late for most of us to use our garden herbs but you might still have garden sage you can use and it is a good technique to remember for next year.  I also used Silver Leaf XV Native Olive Oil from organic grown olives that I buy from Gypsy Whole Foods Warehouse out of Burke's FallsThe first, cold press of the olives is done without added heat and preserves nutrients.

I like freezing as a food preservation method as it reduces food safety risk. Pathogenic bacteria are "in suspended animation" and cannot grow at freezer temps. I discussed food safety of garlic and oil in a previous blog and the same holds true for herbs in oil. According to Health Canada herb oils made fresh for use should not be left at room temperatures. Refrigerate leftovers and use within 7 days, freeze or discard.  If you are going to defrost a whole jar of herb oil puree you should do it in the refrigerator and remember to use it up in a week.

Commercial herbs in oils, and pesto, are required to have an acidifying agent added to prevent growth of harmful micro-organisms during long storage. The acid changes the flavour but it is safe.  Alternately, dehydrated herbs can be added to oil. Follow this link to Oregan State University's Extension Education Service's handout Food Safety & Preservation:
Herbs and Vegetables in Oil.

Makes about 3 cups/750 ml

1 cup  (250 ml) XV olive oil - I used Silver Leaf XV Olive oil from organic grown olives
2 cups (500 ml) fresh herbs like basil, cilantro, lemon balm, mint, parsley, tarragon alone or in a pleasing combination. 


1. Puree the herbs and oil until completely smooth in a blender or food processor.
2. Pour into sterilized jars, label, date and store in freezer. I like to line mine up on the door of the freezer for easy access during cooking.  If your needs are smaller just freeze in ice-cube trays or smaller portions.

Optional additions: hot chile pepper if you want a spicier combination.

The lemon balm (Melissa) shown below freezes well in an herb oil puree.

Woody herbs such as rosemary, sage, thyme, oregano or lemon verbena freeze fairly well on their own but they can also be pureed in oil and frozen for later use. They are quite strong so I only use 1 cup packed leaves to 2 cups pure olive oil.  Remove the leaves from the woody stems before making the herb oil puree.


Oil is high in calories and has on average 120 calories per tablespoon.  Oil provides essential fatty acids and help absorb the fat soluble vitamins A, D, E and K.  Adding some healthy oil to vegetables helps absorption of these fat soluble vitamins.  For instance, using a bit of olive oil on carrots helps your body absorb and use the vitamin A.  Fats are slower to digest than carbohydrate and protein and using healthy fats as part of a well balanced diet helps promote satiety = helps you stay full longer.  In the past it has been suggested that people use a very low fat approach to weight loss but this is actually not a good approach.  Olive oil is also high in monounsaturated fatty acids which protect against heart disease. Extra virgin olive oil is also anti-inflammatory, anti-thrombotic (reduces blood clotting) and anti-hypertensive.

I was surprised to find out that basil is a member of the mint family but not surprised that as a medicinal plant it is high in antioxidants and has antibacterial properties. Fresh basil is high in vitamin K which supports normal blood clotting - 2 tablespoons of chopped fresh basil provide 27% of the RDA of vitamin K.  Basil also contributes vitamin A, manganese, and magnesium (if you eat enough of it!).

This herb oil puree made with extra virgin olive oil and fresh basil has the following in a tablespoon (15 ml): 40 calories, 4.5 g of fat, 0.5 g saturated fat, 0 mg cholesterol, 0 mg sodium, 0 mg carbohydrate.

© Nancy Guppy, RD, MHSc
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1 comment:

Anonymous said...

Hey Nancy,

I freeze oil purees all the time but I pour the mixture on a tray, freeze it then transfer to a plastic bag. I just break off the amount I need. Like peanut brittle....Easier to freeze than jars.