Sorrel: The Sour Herb, Its Oxalic Acid, and How to Cook With It

Sorrel is a leafy herb you grow for one thing above all: sourness. Its leaves taste sharp, green and lemony, and stirred into hot butter or cream they melt into a smooth, tangy sauce, a classic partner for salmon and eggs. That bite comes from oxalic acid, and the same acid is the reason to treat sorrel as a seasoning green, not a salad staple. The numbers below show why.

At a glance

The name

“Sorrel” comes through Old French surele, from sur, “sour,” and ultimately from a Germanic root for sour. The plant was named for the taste of its leaves. The word reached English in the late 14th century.²

The name gets around, too. Plants of the genus Oxalis, in a different family, are called wood sorrel and also have sour leaves.

Flavor and the chemistry behind it

Fresh sorrel tastes sharply sour and green, a bit like unripe apple or lemon peel, with an astringent edge. Cooked, it turns olive-drab and melts into a soft, tangy purée.

The sourness comes from oxalic acid. Sorrel’s distinctive sour taste comes from its high oxalate content, and the same acid gives it its acidity and astringency.

How much oxalate

The best measurements we found come from a 2013 New Zealand study of a green and a variegated cultivar of R. acetosa, analyzed by HPLC:¹

The study found more oxalate in leaves than in stems, and higher levels in bigger, more mature leaves. The authors suggest the soup’s low figures may come from soluble oxalate leaching out during cooking.¹ That’s two cultivars in one study, so don’t read these as typical values for all sorrel.

Origin and where it grows

R. acetosa is native to temperate Eurasia and northwest Africa, and it’s been introduced across much of North America and in a few places in South America, Asia and Africa. Garden sorrel, like sheep sorrel, has naturalized in North America, and sheep sorrel is a weedy European native that’s now widespread there.

You’ll see claims that sorrel was used in ancient Egypt, that sorrel soup was a staple of English cooking in the colonial era, and that English settlers found Native Americans eating it. We couldn’t trace any of them to a source we could open.

How sorrel is used

The main uses: mature leaves cooked as a vegetable, as a flavoring in omelets and sauces, and as the main ingredient of creamed sorrel soup. Young leaves go into salads and get used as a garnish.

A few notes for the kitchen:

• Sauces for fish and eggs. Stir a handful of shredded sorrel into butter or cream at the end of cooking and it melts into a sharp, smooth sauce, a classic partner for salmon and eggs.
• Soups. The leaves soften almost instantly in hot liquid, so sorrel suits puréed soups.
• Raw. Young, small leaves add a hit of acidity to salads. In the 2013 study, bigger, more mature leaves carried more oxalate.¹
• Color. Expect cooked sorrel to lose its bright green.

Buying and storage

We found no grading standard for fresh sorrel. Look for crisp, unwilted leaves with no yellowing. Smaller leaves are milder. We also found no published shelf life from a regulator or extension service, so treat sorrel like other tender greens and use it within a few days.

Nutrition

Per 100 g of raw sorrel, the ANSES Ciqual 2020 table, as presented by Aprifel, lists:³

That table gives no vitamin A or beta-carotene value. Aprifel’s figures are a secondary presentation of the Ciqual table, and we didn’t open the Ciqual record itself. Some of sorrel’s oxalate is soluble, and the study authors recommend preparing it with calcium-rich foods to cut the soluble oxalate.¹ We’re not claiming sorrel prevents anemia, eye disease or cancer. We couldn’t trace those claims to human evidence.

Safety: oxalate

Tuazon-Nartea and Savage conclude that, as a high-oxalate food, sorrel should be eaten only in small amounts, especially by people prone to kidney stones, and suggest eating the leaves now and then, as a delicacy. They point to pesto as a good way to use it, since servings are small, and to cooking sorrel with calcium-rich foods.¹ We found no regulator limit for oxalate in sorrel.

There’s a widely repeated claim that sorrel cooked in aluminum or cast iron picks up a metallic taste. We couldn’t find a source for it. A nonreactive pan for acidic greens is a harmless precaution if you want one.

Substitutes and related pages

Need a swap? See sorrel substitutes.