Boeren-Leidse met sleutels
Boeren-Leidse met sleutels is a semi-hard BOB (Beschermde Oorsprongsbenaming) farm cheese with a fat content in the dry matter of at least 30% and at most 40%, robust to hard, sliceable and, with age, suitable for grating, prepared from semi-skimmed milk which has not undergone any pasteurization heat treatment and to which cumin must be added during preparation. The preparation and conditioning of this specific cheese requires much work, attention and specialist knowledge.
- Geographical area:
Production of Boeren-Leidse met sleutels originated in the river basin of the Oude Rijn in the province Zuid-Holland, in the area surrounding the town of Leiden, after which the cheese was first named some three hundred years ago. The production area, where it has been produced in the traditional way for many years, includes:
-the polder district (hoogheemraadschap) of Rijnland
-the polder district of Amstel en Vecht
-the polder district of Delfland
-the polder district of Schieland
-the greater water board district of Woerden
-the water board district of Leidse Rijn
-the rural district of Westerkoggenland, the Beschoot polder
-the rural district of Giessenlande, the polder of Over- en Neder Slingeland
-the rural district of Udenhout
The area covers some 215,000 hectares in total.
The Vereniging van Boeren-Leidse Kaasmakers was founded on 28 October 1927 with the objective of promoting the interests of the Boeren-Leidse cheese makers. It endeavours to achieve this objective by all legitimate means, including by representing its members at all levels, allowing its members to make use of a registered trade mark for Boeren-Leidse met sleutels, with a view to promoting the sale of their product and regulating the production of the cheese.
"A region which was considered to be particularly good for the dairy industry is the present Netherlands and Belgium. Here there were large pasture lands, particularly along the North Sea, and milk production rapidly became very significant. As early as 1184, cheese was sent from Holland to Paris, and in the following centuries Dutch cheese became an international product. It was named after specific market places, eg near Leiden, Leiden cheese was made; it was characterised by the coat of arms of Leiden, two crossed keys. It is plausible to see in it the origin of the Norwegian Nokkelost (key cheese)".
On account of the favourable location of the production area in relation to the major trading and export centres of Amsterdam and Rotterdam, this type of cheese developed on a large scale and became renowned. As a partially skimmed type of cheese, it was extremely well-suited to long-term storage and was much used as a non-perishable source of protein in ships' provisions and as an export. Because this artisan-produced cheese was traded from the 17th- 18th century in Leiden, production has traditionally been concentrated around that town.
Over the centuries Boeren-Leidse met sleutels has become a unique traditional cheese. Its uniqueness is partly due to the specific characteristics of the milk. Because of the soil conditions and climate, Zuid-Holland has always been ideally suited to dairy farming (polder land). History, man and cattle breeds have all contributed to the specific tradition of this cheese. The cheese is a labour-intensive product prepared in relatively small quantities on farms from their own milk production. The technique for making this cheese has developed over the centuries but it still requires a great deal of work and attention from the maker, including intense manipulation of the curd. The specialist techniques for preparation and conditioning of this "king of cheeses" has been passed down from generation to generation, often on the same farm. The exclusive character of this cheese and its accordingly higher price make it possible for the relatively traditional (in Dutch terms) livestock farms to continue their dairy production.
Farm cheese must be made using milk from not more than two successive milkings. Any quantities of milk not used straight away must be cooled to not more than 10°C immediately after milking. The milk is coagulated with rennet for half an hour at a temperature of 29-30°. Once the milk has been sufficiently coagulated, the curd is chopped into pieces of about 1.5cm. This process takes about 15-20 minutes. After being left for a short time to settle, the curds and whey mixture is heated using hot water and left to ripen further. A small amount of the curd is set aside for the so called "witte bodems" (literally: white bottoms) which prevent the cumin seeds from collecting in the rind on the smooth sides of the cheese. The rest of the curd is mixed with cumin seed, at a ratio of about 75g of seed per 100 litres of milk.
Pressing is carried out in two stages. During the second stage each cheese is indelibly stamped with the imprint of two crossed keys circled by the words "Boeren-Leidse-met-sleutels". Next the cheese is placed in brine at a strength of 20% for five or six days. The rind of the "Boeren-Leidse met sleutels" is coloured red using annatto and/or treated with a red/red-brown coloured cheese rind treatment product. cheeses weighing three kilograms or more are kept for at least 13 days at a temperature óf at least 12°.
Reference: The European Commission