9 - Culinary use of Rhubarb

Rhubarb or "pie plant" is prized for use in pies, tarts, and sauces. Only the petioles are eaten, although herbal remedies use the leaves and roots. The high levels of oxalic acid and other compounds within the leaves are toxic to humans. The petioles contain lower levels of oxalic acid and, primarily, malic acid. ³²

9.1 - Harvesting and Preparation

Rhubarb is sold by the "bunch" which is usually 2 to 2-1/2 lbs., 1 lb. cooked yields 3/4 cup. When buying Rhubarb choose fresh crisp stalks, and peel off any stringy covering before use. Stand the stalks in cold water for an hour or so to refresh them before cooking. The stalks can be stored for 2-4 weeks at 32­ F. A 1 pound bunch contains 3-5 stalks. Before use, discard any leaves and trim the ends. Completely peeling rhubarb is unnecessary. Rhubarb requires sweetening to minimize the extreme tartness. It can be served as a sauce over ice cream, combined with fresh strawberries, or made into pies, tarts, puddings, breads, jam, jellies, and refreshing beverages (skip ahead to the recipes).

Figure 9.1: Red Rhubarb Stalks Photo Credit

The time of harvest is dependent upon the variety as well as on the location and temperature. With varieties that produce many seed stalks, harvesting should begin before the seeds start to turn color. Home gardeners should remove the seed stalks when they first appear (See What to do about Seedpods). Generally, harvesting begins in late May or early June, with an option of a second harvest made in late August. A commercially available mechanical Rhubarb harvester can recover 60 to 70% of the crop in a once-over harvest. Approximately 25% of Michigan's Rhubarb is harvested twice. The stalks should be firm at harvest. If they are harvested too late they become pithy and tough. In Maryland I can continuously harvest from 3 plants starting in early May and continuing through to the end of the summer if I water regularly. I pick 2-4 stalks at a time from each plant and can do this almost weekly. I leave most of the plant intact to keep it actively growing. Lack of water and the more intense heat in the hotter parts of the summer seems to be what ends my harvest.

Harvesting should be delayed until the second year following planting to permit accumulation of root reserve. During the second year, a light harvest may be taken and normal harvests may begin in the third year. Stalks may be clean cut, taking the entire plant at the soil line or harvesting sequentially by pulling the stalks at the prime size over a period of 4-6 weeks. Do not remove more than 2/3 of the fully developed petiole from any plant at harvest. As stalks are cut, leaves are removed and left in the field or they can be composed (see Composting rhubarb leaves).

Select petioles that are bright pink, crisp and free of disease or insect damage. Young, dark pink, smaller diameter petioles are sweeter and more tender than thick, long green ones, but this also depends and the particular variety of Rhubarb. Don't cut the Rhubarb stalks from the plant, but instead snap them off. They will come away quite easily and this is much better for the plant. I grab a stalk right down where it emerges from the ground, and use a sort of rocking, twisting motion. Visualize snapping away a single celery stalk from the bunch. If the stalk is grasped too high it snaps in two. At any given time, harvest less than 1/3 of the stalks from any one plant. Rhubarb may be harvested later but very few stalks should be taken from any one plant. ^{1 2 3 4 5 6 7 8}

9.2 - Storing Rhubarb

Rhubarb, if not used immediately, can be stored by refrigeration, caning, freezing or drying. Here are some very basic procedures for each of these methods.

9.2.1 - Refrigeration

Cut all of the leaf away from the Rhubarb petiole and the petioles will keep well in the refrigerator for two to three weeks in sealed plastic bags. ^{9 10} .

9.2.2 - Caning

• An average of 10-1/2 pounds is needed per canner load of 7 quarts; an average of 7 pounds is needed per canner load of 9 pints. A lug weighs 28 pounds and yields 14 to 28 quarts--an average of 1-1/2 pounds per quart.
• Select young, tender, well-colored stalks from the spring or late fall crop.
• Trim off leaves. Wash stalks and cut into 1/2-inch to 1-inch pieces. In a large saucepan add 1/2 cup sugar for each quart of fruit. Let stand until juice appears. Heat gently to boiling. Fill jars without delay, leaving 1/2-inch headspace. Adjust lids and process.
• Process directions for canning Rhubarb in a boiling-water, a dial, or a weighted-gauge canner are given in Table 1, Table 2, and Table 3.

Figure 9.2: Rhubarb Stalks (Victoria)

Table 9.1: Recommended process time for Rhubarb, stewed in a boiling-water canner
¹¹

Table 9.2: Process Times for Rhubarb in a Dial-Gauge Pressure Canner
¹²

Table 9.3: Process Times for Some Acid Foods in a Weighted-Gauge Pressure Canner
¹³

9.2.3 - Freezing

Choose firm, tender, well-colored stalks with good flavor and few fibers. Wash, trim and cut into lengths to fit the package. Heating Rhubarb in boiling water for 1 minute and cooling promptly in cold water helps retain color and flavor.

Dry Pack Method: Pack either raw or preheated Rhubarb tightly into containers without sugar. Leave head space (see table below). Seal and freeze.

Syrup Pack Method: Pack either raw or preheated Rhubarb tightly into containers, cover with cold 40 percent syrup (see table below). Leave head space (see table below). Seal and freeze.

Figure 9.3: Rhubarb Stalks (several varieties)

Table 9.4: Head space to allow between packed food and closure
¹⁴

Table 9.5: Syrups for Use in Freezing Fruits
¹⁵

9.2.4 - Drying

Wash and remove any blemished areas. Cut off the pulpy ends. Cut into 1/2-inch strips or 1/2-inch cubes. To decrease some of the acidity in the Rhubarb (and reduce the amount of sugar needed to sweeten), pour boiling water over the pieces and let sit for 3 to 5 minutes. Drain. A characteristic of the dried product will be brittle. ¹⁶

9.3 - Nutritional information

Rhubarb is 95% water and contains a fair source of potassium, contributes minor amounts of vitamins, and is low in sodium. Rhubarb's crisp sour stalks are rich in vitamin C, dietary fiber and calcium, although the calcium is combined with oxalic acid and so is not easily absorbed by the body. Rhubarb is somewhat acidic (pH 3.1-3.2) but in most recipes this is normally offset by sugar. One cup diced Rhubarb contains about 26 calories. ^{17 18 19}

Readers of The Rhubarb Compendium may be interested in...

Uncommon Fruits & Vegetables: A Commonsense Guide
Elizabeth Schneider, Soun Vannithone (Illustrator), Pam Hoenig (Editor)

Just as ginger, bean sprouts, and avocados were once strange, exotic substances, so Vidalia onions, fava beans, and passion fruit are becoming more common in stores nationwide.  Elizabeth Schneider discusses each of 80 fruits and vegetables, its origins, history, and appearance, its flavor, uses, and nutritional highlights. Detailed methods of selection, storage, and preparation lead to more than 400 easy-to-follow recipes designed to bring out the best in each fruit and vegetable. If you are interested in trying new food, you must have this book. [b12]

Footnotes:

1. 03900106 (Growing Rhubarb),  http://lep.cl.msu.edu/msueimp/htdoc/mod03/03900106.html
2. Rhubarb, http://aggie-horticulture.tamu.edu/plantanswers/vegetables/rhubarb.html
3. Rhubarb, http://www.veg.org/veg/Orgs/VegSocUK/Recipes/rhubarb2.html,
4. 01701479 (Rhubarb, Pieplant.), http://lep.cl.msu.edu/msueimp/htdoc/mod03/01701479.html,
5. 01701480 (Facts about Rhubarb), http://lep.cl.msu.edu/msueimp/htdoc/mod03/01701480.html
6. 03900041 (NET WEIGHTS AND PROCESSED YIELDS OF FRUIT AND VEGETABLES IN COMMON RETAIL UNITS), http://lep.cl.msu.edu/msueimp/htdoc/mod03/03900041.html, "Net Weights and Processed Yields of Fruits and Vegetables in Common Retail Units" by C. M. Sabota and J.W. Courter Department of Horticulture, University of Illinois at Urbana - Champagne, College of Agriculture Cooperative Extension Service of the Michigan State University Extension Information Management Program Home Horticulture Database
7. rhubarb2, http://ftp.lysator.liu.se/pub/gardening/Edibles/rhubarb2, a USENET posting From: Barry Carlson@mindlink.bc.ca (Barry Carlson), Subject: Rhubarb, Date: Thu, 20 May 1993 01:39:06 GMT
8. Selecting, Preparing and Canning: Rhubarb--Stewed (http://www.agen.ufl.edu/~foodsaf/he246.html)
9. 03900106 (Growing Rhubarb),  http://lep.cl.msu.edu/msueimp/htdoc/mod03/03900106.html
10. Rhubarb, http://aggie-horticulture.tamu.edu/plantanswers/vegetables/rhubarb.html
11. Selecting, Preparing and Canning: Rhubarb--Stewed (http://www.agen.ufl.edu/~foodsaf/he246.html)
12. Selecting, Preparing and Canning: Rhubarb--Stewed (http://www.agen.ufl.edu/~foodsaf/he246.html)
13. Freezing Rhubarb, http://www.agen.ufl.edu/~foodsaf/he419.html, This document was extracted from Bulletin 989, "So Easy to Preserve," produced by the Cooperative Extension Service, the University of Georgia, College of Agricultural and Environmental Sciences.
14. Freezing Rhubarb, http://www.agen.ufl.edu/~foodsaf/he419.html, This document was extracted from Bulletin 989, "So Easy to Preserve," produced by the Cooperative Extension Service, the University of Georgia, College of Agricultural and Environmental Sciences.
15. Freezing Rhubarb, http://www.agen.ufl.edu/~foodsaf/he419.html, This document was extracted from Bulletin 989, "So Easy to Preserve," produced by the Cooperative Extension Service, the University of Georgia, College of Agricultural and Environmental Sciences.
16. Drying Rhubarb, http://lep.cl.msu.edu/msueimp/htdoc/mod01/01600757.html
17. Rhubarb, http://aggie-horticulture.tamu.edu/plantanswers/vegetables/rhubarb.html
18. Rhubarb, http://www.veg.org/veg/Orgs/VegSocUK/Recipes/rhubarb2.html,
19. Untitled, http://agweb.clemson.edu/Hort/drd/Rhubarb.html