What is Grüne Soße?
Grüne Soße, or green sauce, is a regional German variation on the global herb sauce theme that includes Italian salsa verde, French sauce verte and Argentinian chimichurri. This speciality of Frankfurt, known in the local dialect as Grie Soß, is a cold, creamy sauce made with finely chopped fresh herbs, most commonly with halved boiled eggs and boiled potatoes.
Grüne Soße can be found on the menu in traditional Apfelwein (cider) taverns and German restaurants in and around Frankfurt and wider Hessen, as well as in nearby parts of the neighbouring state of Rheinland-Pfalz. It’s enjoyed across the region not just with eggs and potatoes, but also with slices of tender boiled beef brisket (Tafelpitz or Ochsenbrust), fillets of white fish, or a warm chunk of Fleischwurst. In Frankfurt, you can order Grüne Soße with a breaded pork or veal Schnitzel, which you’ll find on the menu as a Frankfurter Schnitzel.
The origins of Grüne Soße
There’s much disagreement about how and when Grüne Soße first made its entrance into the regional culinary repertoire. There are suggestions that it came to Frankfurt¹ from France, Italy or Asia, but wherever it originated, the oldest recorded printed recipe for Grüne Soße is to be found in an 1856 cookbook by Wilhelmine Rührig in which a selection of “quite a lot of very finely chopped herbs” are mixed with a hard-boiled egg yolk, salad oil, mustard, vinegar and seasoning.
Ein hart gesottenes Eigelb wird mit 2 Löffel Salatöl 1/4 Stunde ganz fein verrührt, mehrere Löffel feiner Senf darunter gemischt und ziemlich viel ganz fein gehackte Gewürzkräuter als Borasch, Estragon, Petersilie, Körbel, Schnittlauch und Pimpernell alsdann Essig, Salz und Pfeffer dazu geben.
The recipe has changed very little as it’s made its way down through the generations, but you’d be pressed to find a definitive list of Grüne Soße ingredients today. Though in addition to the herbs the sauce always involves chopped boiled eggs, mustard, oil and vinegar, the creaminess might come from sour cream, crème fraîche, buttermilk or yoghurt, and people make all sorts of other adjustments, too. I’ve heard that some people use mayonnaise, but according to most Frankfurters I’ve spoken to, that’s nothing short of sacrilegious.
Frankfurter Grüne Soße herbs
Whatever else you put into your Grüne Soße, mess with the herbs at your peril. In 2016, the Association for the Protection of Frankfurter Grüne Soße won protection of geographical indications and designations of origin from the EU for the herbal blend. Only bundles containing specific quantities of seven specific herbs – sorrel, chervil, chives, parsley, burnet, cress and borage – grown in Frankfurt or a number of nearby locations can be called Frankfurter Grüne Soße. (The blend of herbs is known as Frankfurter Grüne Soße; the sauce made with them is Grüne Soße.)
If you’d like to delve into the details of the Frankfurter Grüne Soße herbs and quantities thereof, have a look at the official application for the protection of geographical indications and designations of origin for Grüne Soße in the Official Journal of the European Union – it makes for wonderfully nerdy reading.
Though the EU ruling states that the herbs can be grown throughout Frankfurt and in a number of its surrounding towns and villages, the true home of the herbs is considered to be the southern Frankfurt district of Oberrad, where they’ve been grown for generations alongside lamb’s lettuce and rocket. A monument to Grüne Soße was built there in 2007 as a homage to both the sauce and the district itself; seven small glass houses in various shades of green stand in a line, symbolising each of the seven herbs.
The first harvest of Frankfurter Grüne Soße takes place in early spring to coincide with the official first day of the Grüne Soße season, Gründonnerstag (Green² or Maundy Thursday, a Christian holiday that commemorates Christ’s last supper). The herb blends are bundled together by hand and rolled carefully into large white paper packages printed in green with their name and contents. The bundles are then sold at markets in Frankfurt and across the region. Grüne Soße season officially ends much later in the year with the arrival of the first frost.
How to make Grüne Soße
Making Grüne Soße at home is very straightforward, but you do need to get your herbs right, and I for one have found it very difficult to get hold of all seven of them in the required quantities outside this region (and, indeed, the country). There’s nothing to stop you making substitutions, but though making adjustments will still create a very good sauce, it just won’t taste like the real deal.
Having tested many versions over the years, I do have my own favourite recipe, which combines the usual list of ingredients with a good helping of crème fraîche. Prolific German food blogger Oma, who moved from Frankfurt to the US in 1989 and grows her own Grüne Soße herbs in Maryland, makes hers with yoghurt and sour cream.
Where to eat Grüne Soße
If you’re visiting Frankfurt, I’d highly recommend stopping in at a traditional restaurant or Apfelwein tavern and giving it a try (with a glass of local cider alongside). Eier mit Grüne Soße (eggs with green sauce) is a reliable option for vegetarians having trouble navigating the rather meat-heavy Frankfurter menus. I’ll be publishing a list of recommended places to try it soon.
¹ Kassel, a city 200km north of Frankfurt, also claims the origins of Grüne Soße. I intend to investigate this throughly when I visit, but until then, I’m sticking with Frankfurt’s green sauce
² It isn’t, rather disappointingly, called Green Thursday in connection with the start of Spring. The “Grün” in Gründonnerstag comes from the verb greinen, to whine or lament, referring to the Middle Age custom of escorting weeping penitents back to church on this day in the Christian calendar. [Source.]