A Mathematician Who Wanted to Be an Olympian and Ended Up Making Wine
Start with the biography, because it explains everything. Ron Langeveld studied theoretical mathematics at Leiden University, decided a PhD meant years alone with a computer and a lot of formulas, passed on that, and went to work writing software for a Swedish telecom company. Good salary, lease car, the whole package. He quit anyway. What he actually wanted was to compete for the Dutch Olympic canoeing squad, and for some years he trained full-time trying to get there. He didn't. The details of exactly when, and at what level he raced, are not publicly documented in any source this writer could find — so take the Olympic framing as his own telling of it, which may well be accurate and is at minimum honest about failure. And then — this is the part where you either understand the man or you don't — he planted a vineyard.
The first hectare went in the ground in 2005 on his parents' land in the hamlet of Dassemus, just south of Breda in Noord-Brabant, planted with friends and family over what must have been a long few days. The estate is named after the hamlet. That is the entire explanation for the name. There is no story behind it beyond: this is where it is.
The Partner
Monique van der Goes spent her career as a lawyer and director in the Dutch judiciary, a long stretch of it in Brussels among the European institutions. She had been around Dassemus from the beginning — in the way that partners of driven, slightly obsessive people tend to be around things, which is to say more centrally than the official record ever reflects. In 2023 she became a full-time participant in the business. That is a significant thing to do after a long legal career, and she did it. What that says about what Dassemus had become by then is probably more eloquent than anything this article can add.
PIWIs or Nothing, and He Means Nothing
The Netherlands is humid. Oidium, Peronospora, Botrytis cinerea — the full cast of fungal problems is present and patient. The normal response in viticulture is a spray calendar: copper, sulphur, fungicides, repeat every few weeks and pray for a dry August. Langeveld decided not to. From the first vine, Dassemus has grown only PIWI varieties — fungal-resistant hybrids — and the estate says it sprays nothing at all, not even copper or sulphur, which even most biodynamic producers use. That is an extraordinary claim. It is also, frankly, unverifiable from the outside without detailed seasonal records, so it is reported here as the estate's own position.
Reaching that position took testing more than 25 resistant cultivars and discarding the ones that couldn't cope with Dutch conditions unaided. Cabertin, Pinotin, Cabernet Blanc are gone. The white varieties currently on the estate — and this is a snapshot, not a permanent list, because the lineup has shifted before and may shift again — are Solaris, Souvignier Gris, Muscaris, Sauvignon Soyhières, Sauvignac, Riesel, and Johanniter. Reds are Rondo, Cabernet Cortis, Cabernet Cantor, Cabernet Jura, Baron, and Monarch. Langeveld rates Souvignier Gris as his most promising white. Johanniter he considers his least robust — his own view, not a viticultural consensus — but it makes something close to a Riesling, so it stays. Twenty years of trial and error compressed into thirteen varieties. That is the actual cost of growing grapes in the Netherlands without reaching for anything.
Wild Fermentation, No Filter, a Little Sulphite at the End
Since 2020 every still wine at Dassemus ferments with wild yeasts from the vineyard itself. The estate does not explain in detail what changed in 2020 or what was done before, only that the approach has been consistent since then. No commercial yeasts, no filtration. Langeveld's explanation for why it works is straightforward: he never killed his wild yeasts with fungicide, so they are plentiful, and the fermentations start almost immediately after harvest.
The range, as the website currently describes it — not every wine is made every year, and compositions shift between vintages, so verify before buying: a white from Solaris, Sauvignac, and Johanniter with one night of skin contact; a rosé from Cabernet Jura and Cabernet Cantor with minimal skin contact; an orange from Souvignier Gris and Muscaris on skins for 25 days, aged across stainless steel, French oak barrique, and a ceramic Clayver amphora; a red from Cabernet Cantor, Cabernet Jura, and Monarch. Two sparkling wines by traditional method, two years on bottle. At bottling, sulphite under 10 mg/l goes in when considered necessary. That is it. Earlier sources describe the red as a Rondo varietal — the lineup has moved, and will probably move again.
The First Biodynamic Vineyard in the Netherlands — With an Asterisk
Demeter certification arrived in August 2021, and the estate describes itself as the first biodynamic vineyard in the Netherlands. This claim travels widely and may be accurate in spirit even if the fine print is complicated. Biodynamic certification requires a conversion period of several years, so the practices predate 2021 by some margin. But at least one other Dutch estate — Wijngaard de Kruithof in Ophemert — is reported to have received Demeter certification earlier, in 2018. So "first" is probably not quite right, or at least not provable from available sources. Prominent, pioneering, and serious about it: those hold up fine.
What biodynamic farming looks like at Dassemus is not mysterious. Soil fed with compost and manure from the estate's own goats and chickens. Nitrogen via green manures that are sown and cut back. Vine rows alternating between grass kept short enough to drive on and unmown strips left for insects. The estate dug ponds — partly for the frost-protection sprinklers that run when spring temperatures drop, partly, it seems, because a pond turns out to be good for sand martins, kingfishers, frogs, and amphibians. There is a walking trail behind the estate that Natuurmonumenten maintains. Rubber boots recommended. None of this reads like it was added afterwards for the website. The logic was there from 2005 and the rest accumulated around it.
What Else Comes Out of the Cellar
Grape skins after pressing become The Spirit of Dassemus — grappa-style, 40% alcohol, part of it four years in French oak developing cocoa and caramel. Other fruit gets distilled too: apples, raspberries, cherries. The apple cider is made from Brabant fruit that supermarkets rejected for being the wrong size, which is one of those agricultural absurdities that biodynamic winemakers seem drawn to fixing. A second fermentation on grape skins produces something called Cecider — cider and wine sharing a tank, essentially. Baronie Distillers, an organic whisky operation, is listed as operating on the premises; the estate mentions it but detail beyond that is thin in available sources, so it stays here as a note rather than a fact. The first harvest at Dassemus was in 2007 and produced around 700 litres. A year later, 6,000. Earlier sources describe the estate at four hectares and 16,000 vines; the current figure is six hectares and more than 22,000, which reflects phased expansion rather than any inconsistency — the last two hectares were added in 2020.
Getting There, Getting a Bottle
The webshop delivers within the Netherlands. International distribution is not documented on the estate website, though specialist importers in other countries do carry the wines — availability outside the Netherlands is worth researching separately. The on-site shop is described as open daily in principle; calling ahead is sensible. Groups of ten or more can arrange guided tours with tastings outside the harvest window, which runs from mid-September to late October and rules out weekend visits during that period. Individual visitors can walk the self-guided trail through the vineyard. In 2017, Langeveld collaborated with wine importer Marnix Rombaut and writer Simon Woolf — later the author of Amber Revolution — on what they called the first genuine Dutch orange wine, from Souvignier Gris. Other Dutch estates had done extended skin contact on whites before that, so the "first" is arguable. What is less arguable is that the collaboration put Dassemus on a map it has stayed on.