is a Flemish word for a rather large, bucket-shaped, perforated, hand-operated brewing vessel. Early versions were made from wicker; later they were made of copper. The stuykmanden is closely associated with the Flemish wheat beer brewing tradition, specifically the brewing of witbier (bière blanche) in the traditional manner.

When witbier was brewed in preindustrial times, several brewhouse vessels had to be in simultaneous use. In one of these vessels the major part of the mash, called the goed sakken, containing coarsely milled barley malt and both raw wheat and raw oats, was mashed in cold water and mixed by hand. After a rest, the resulting wort had to be drawn from this vessel and transferred to one of the wort kettles. But the combined factors of the gummy grist composition and the low temperature made the mash very viscous and starchy. This mash was impossible to run off through the false bottom of the mash tun, and this is where the stuykmanden came into use. It was immersed in the mash from the top, forcing the liquid to run through the perforations into the interior of the stuykmanden, from where it could be siphoned off into buckets that were then emptied into the wort kettle.

Later in the brewing process, the stuykmanden was also in use for drawing of worts of increasing temperature and decreasing strength in the extremely elaborate and complicated process of heating water and wort in some vessels, holding others, transferring water and weak worts onto the two different mashes, and transferring worts to the kettles. Not surprisingly, the use of this brewing practice and the stuykmanden have not survived into the modern era.

See also goed sakken.