Herb and Spice of the Week - Horseradish

Sections of roots of the horseradish plant

Horseradish (Armoracia rusticana, syn. Cochlearia armoracia) is a perennial plant of the Brassicaceae family (which also includes mustard, wasabi, broccoli, and cabbage). The plant is probably native to southeastern Europe and western Asia. It is now popular around the world. It grows up to 1.5 meters (4.9 feet) tall, and is cultivated primarily for its large, white, tapered root.

The intact horseradish root has hardly any aroma. When cut or grated, however, enzymes from the now-broken plant cells break down sinigrin (a glucosinolate) to produce allyl isothiocyanate (mustard oil), which irritates the mucous membranes of the sinuses and eyes. Grated mash should be used immediately or preserved in vinegar for best flavor. Once exposed to air or heat it will begin to lose its pungency, darken in color, and become unpleasantly bitter tasting over time.

Foliage of the horseradish plant

Horseradish is perennial in hardiness zones 2–9 and can be grown as an annual in other zones, although not as successfully as in zones with both a long growing season and winter temperatures cold enough to ensure plant dormancy. After the first frost in the autumn kills the leaves, the root is dug and divided. The main root is harvested and one or more large offshoots of the main root are replanted to produce next year's crop. Horseradish left undisturbed in the garden spreads via underground shoots and can become invasive. Older roots left in the ground become woody, after which they are no longer culinarily useful, although older plants can be dug and re-divided to start new plants. The early season leaves can be distinctively different, asymmetric spiky, before the mature typical flat broad leaves start to be developed.




Cooks use the terms "horseradish" or "prepared horseradish" to refer to the grated root of the horseradish plant mixed with vinegar. Prepared horseradish is white to creamy-beige in color. It will keep for months refrigerated but eventually will darken, indicating it is losing flavor and should be replaced. The leaves of the plant, while edible, are not commonly eaten, and are referred to as "horseradish greens", which have a flavor similar to that of the roots.




Horseradish sauce made from grated horseradish root and vinegar is a popular condiment in the United Kingdom and in Poland. In the UK it is usually served with roast beef, often as part of a traditional Sunday roast, but can be used in a number of other dishes also, including sandwiches or salads. A variation of horseradish sauce, which in some cases may substitute the vinegar with other products like lemon juice or citric acid, is known in Germany as Tafelmeerrettich. Also popular in the UK is Tewkesbury mustard, a blend of mustard and grated horseradish originating in medieval times and mentioned by Shakespeare (Falstaff says: "his wit's as thick as Tewkesbury Mustard" in Henry IV Part II. A very similar mustard, called Krensenf or Meerrettichsenf, is popular in Austria and parts of Eastern Germany.

In the U.S., the term "horseradish sauce" refers to grated horseradish combined with mayonnaise or salad dressing. Prepared horseradish is a common ingredient in Bloody Mary cocktails and in cocktail sauce, and is used as a sauce or sandwich spread. Horseradish cream is a mixture of horseradish and sour cream and is served alongside au jus for a prime rib dinner.

The distinctive pungent taste of horseradish is from the compound allyl isothiocyanate. Upon crushing the flesh of horseradish, the enzyme myrosinase is released and acts on the glucosinolates sinigrin and gluconasturtiin, which are precursors to the allyl isothiocyanate. The allyl isothiocyanate serves the plant as a natural defense against herbivores. Since allyl isothiocyanate is harmful to the plant itself, it is stored in the harmless form of the glucosinolate, separate from the myrosinase enzyme. When an animal chews the plant, the allyl isothiocyanate is released, repelling the animal. Allyl isothiocyanate is an unstable compound, degrading over the course of days at 37 °C. Because of this instability, horseradish sauces lack the pungency of the freshly crushed roots.




In Central and Eastern Europe horseradish is called khren (in various spellings like kren) in many Slavic languages, in Austria, in parts of Germany (where the other German name Meerrettich isn't used), in North-East Italy, and in Yiddish (כריין translitered as khren).

A bottle of Heinz horseradish sauce

There are two varieties of khreyn. "Red" khreyn is mixed with red beet (beetroot) and "white" khreyn contains no beet. It is popular in Ukraine (under the name of хрін, khrin), in Poland (under the name of chrzan), in Lithuania (krienai) in the Czech Republic (křen), in Russia (хрен, khren), in Hungary (torma), in Romania (hrean), in Lithuania (krienai), in Bulgaria (хрян, khryan), and in Slovakia (under the name of chren). Having this on the table is a part of Christian Easter and Jewish Passover tradition in Eastern and Central Europe.

* In parts of Southern Germany like Franconia, "Kren" is an essential component of the traditional wedding dinner. It is served with cooked beef and a dip made from lingonberry to balance the slight hotness of the Kren.
* In Poland, a variety with red beet is called ćwikła z chrzanem or simply ćwikła.
* In Ashkenazi European Jewish cooking beet horseradish is commonly served with gefilte fish.
* In Transylvania, Red beet with horseradish is also used as a salad served with lamb dishes at Easter called sfecla cu hrean and other Romanian regions.
* In Serbia, ren is an essential condiment with cooked meat and freshly roasted suckling pig.
* In Croatia, freshly grated horseradish (Croatian: Hren) is often eaten with boiled ham or beef.
* In Slovenia, and in the adjacent Italian regions of Friuli Venezia Giulia and nearby Italian region of Veneto, horseradish (often grated and mixed with sour cream, vinegar, hard-boiled eggs, or apples) is also a traditional Easter dish.
* Further west in the Italian regions of Lombardy, Emilia-Romagna, and Piedmont, it is called "barbaforte (strong beard)" and is a traditional accompaniment to bollito misto; while in north-eastern regions like Trentino-Alto Adige/Südtirol, Veneto and Friuli-Venezia Giulia, it is still called "kren" or "cren". In the southern region of Basilicata it is known as "rafano" and used for the preparation of the so-called "rafanata", a main course made of horseradish, eggs, cheese and sausage.
* Horseradish is also used as a main ingredient for soups. In the Polish region of Silesia, horseradish soup is a common Easter Day dish.