- There are various radicchios, all types of chicory.
- Common varieties such as round radicchio and red endive are widely grown. But the more niche varieties, such as Tardivo or Castelfranco, are almost exclusively grown in the Veneto region of Italy where they have a Protected Geographical Indication (PGI) designation.
- Some radicchios are 'forced'. This is a process whereby they are deprived of light which enhances the red colouration and reduces the green of the chlorophyll.
- D & J Hayward in Wiltshire is an example of a UK grower of standard round 'Chioggia'.
Varieties of radicchio
There are six key varieties of radicchio, although you may also find rarer ones such as yellow radicchio.
The harvest of Tardivo, the later variety pictured below, begins in November after one or two frosts. (The cold snaps benefit the plants). The season then continues to late March. Scroll down to 'Growing and harvesting' to see the story of how it's grown.
Castelfranco is famous for its speckled (a.k.a. variegated) leaves that dazzle after a period of blanching. Traditionally, the plant is harvested after the first frosts then forced in sand to improve colour and flavour. This plant is said to be a cross between radicchio and escarole.
(These are often eaten raw but here's a cooking tip: dip the leaves first in a mixture of white wine and water and then wrap a parcel of cheese before baking in the oven.)
ROSA / PINK
Pink radicchio, which is also known as Rosa del Veneto, is known for its gorgeous, pale pink leaves. The main season - for sand forced crops - is around November to March although you may find modern varieties outside of this window. Traditionally, this plant is forced in sand to improve colour texture and flavour. However some growers use modern varieties which do not require this process.
ROSA DEL FRIULI
Rosa del Friuli, also known as Rosella di Lusia, is becoming increasingly fashionable. This stunning plant, with its jagged leaves, is in season from mid December until mid February.
These are harvested straight from the field after the first frosts and typically eaten raw. The outer leaves are stripped off leaving these beautiful rosettes.
Precoce is an earlier variety. The main harvest period is from early September to late November, although it can be grown all year round using techniques such as fleecing.
Precoce does not undergo the same forcing process in water as Tardivo. The outer leaves are tied up in the field, shielding the heart from sunlight.
Growing and harvesting
Here's the process for tardivo, which is unique to this plant. Top Italian producer Claudio Bellia grows nearly half a dozen different radicchios, a type of chicory, with total annual production of 500-600 tonnes from a patchwork farm of 200 hectares.
The plants are harvested from the fields and stored temporarily in sheds.
Next, the workers pack the plants into special metal crates so that the roots can be immersed in water in the dark for 15-20 days. This nutrient-rich pure spring water is pumped from a natural lake deep underground and emerges at around 16-17° Celsius.
This stage encourages the heart of the plant to grow without exposure to sunlight and is called "imbianchimento" (whitening). The inner leaves lose their green colour and slight bitterness, which derives from the chlorophyll, and turn their distinctive shade of red and become somewhat sweeter as a result.
After a couple of weeks, the radicchio is taken to the pack house, where workers strip off the outer leaves.
The roots of the plants are trimmed to 8-10cm and then the radicchios are cleaned in water.
In Italy, classic recipes include: raw as a salad (dressed with a little olive oil and salt, and occasionally vinegar); in risotto; with sausage and polenta; grilled Tardivo or Precoce wrapped in bacon.
You'll also find radicchio on pizza, in lasagna or with squid, which is a traditional Christmas dish.
Here is an involtini - radicchio wrapped in pancetta - from Bacchette e Pomodoro:
At time of writing, chefs using radicchio in innovative ways here in the UK include charred January King, tardivo, radish and miso dressing at The Ninth in Fitzrovia.
At Cub in Hackney, they compress the radicchio in buttermilk, roast, season and combine with a green sauce made from Cornish young nettle tops, watercress and three cornered-leek:
In restaurants such as San Martino in the Veneto, radicchio is given the full Michelin treatment. The first picture below shows radicchio wrapped around "Pastin", a local sausage:
Here's radicchio used for a tortellini stuffing and served in a borlotti cream at Pizzeria La Finestra in Aachen, Germany: