Eight generations ago, in 1809, the Lindemans family owned a farm in Vlezenbeek near Brussels. They decided to intensify Lambic brewing activities during winter, when less farm work had to be done. The farm produced wheat and barley, the raw materials of the Lambic.
"Lambic" is infamous in that it is more vineous than your regular Belgian style of beer. This style can only truly be produced in a specific region of Belgium from local barley, unmalted wheat, and aged or "debittered" hops, and matured in oak casks in the breweries cellars.
These casks harbour various local wild yeast and bacteria, causing the wort to ferment without the addition of a commercial yeast strain (known as spontaneous fermentation). The result is a light bodied but intensely sour and complex beer - the tartness is akin to a hard cider or white wine.
To make the beer more palatable en-mass- most people are scared of the sour and funky flavours, breweries often add fruit to the casks mid-fermentation.
Kriek (cherries), framboise (raspberries), apple and cassis (blackberries) are the most common additions.
The beer takes on intense fruit flavours and colours when brewed in this manner, though interestingly the fruit does not add any sweetness to the beer. Sweet versions are produced by sweetening before packaging. Both adding fruit and sweetening are methods of "taming" these wild brews, by offering balance to the often intense sourness.
Lindemans is a highly regarded producer of lambics. The brewery produces the not-so-traditional sweet versions of the style which have gained world wide popularity.