By 1900, Paul Cantillon and his wife Marie Troch began a gueuze blending business in the industrial quarter of Cureghem which was part of the southern Brussels community of Anderlecht. The brewery was located in a very busy area near the Bruxelles-Midi train station, the Mons boulevard, and the canal that ran through the city. Jean-Pierre Van Roy, who wrote the forward to [[Books#La_Gueuze_gourmande|''La Gueuze Gourmande'']] calls the period between 1900 and 1937 the ''"première periode de la brasserie"''. During these first thirty-seven years Cantillon never actually brewed a beer. Instead, they bought lambic from a variety of producers in the area to blend and sell on their own considering Cantillon a ''biersteker'' (beer blender) and ''marchand de bières'' (beer merchant). They would house their beers at Gheudestraat 56-58 where the brewery is located today.[[The_Language_of_Lambic#The_Town_of_Lembeek|Lembeek]] area. By 1894 Auguste had bought the Vandezande-Van Roy brewery located in Lembeek’s Hondzocht district.
Paul and Marie had four children, two sons named Robert and Marcel, and two daughters named Georgette and Fernande. The early years of Cantillon produced unblended lambic, mars, faro, gueuze, and kriek, and framboise. After the First World War, Paul was ready to expand the business and bring his two sons into the fold. Finally, in 1937 Paul, Robert, and Marcel purchased the Brasserie Nationale du Néblon located in Ouffet which had closed the previous year in 1936. They moved the brewing equipment to its current location and the first batch of Cantillon’s own beer was brewed in 1938 shortly before the brothers were called to mobilize for World War II.<ref name=“GeuzeKriek”>Jef Van den Steen, [[Books#Geuze & Kriek: The Secret of Lambic Beer|Geuze & Kriek: The Secret of Lambic Beer]], 2012</ref>
During the Second World War, with supplies in demand for the soldiers, it was more difficult to continue to brew beers. The period during the war saw the brewery at a near standstill. The immediate post-war years did not see the same demand and production of beers as the 1930’s had. To make matters worse, a massive heat wave in Belgium destroyed many brewery’s stocks including Cantillon’s. Sometime around 1950 the brewery began to recover and reached an all-time high production in 1955. Paul Cantillon passed away in 1952, while his wife Marie lived until 1958. Starting in 1960 the demand for traditional gueuze and lambic began to decline once again and Marcel sold his share to Robert and left the business. Robert, too, was on his way out of the brewing business when his only daughter, Claude, married Jean-Pierre Van Roy. By 1969-1972 Van Roy had taken the reigns of the brewery.
To keep the brewery afloat, Van Roy sweetened his gueuze with artificial sweeteners to keep up with current tastes. Sadly, this did not help the brewery and it continued to operate at a loss. By 1975 Jean-Pierre began to abandon the artificial sweeteners and stopped the practice altogether by 1978. In 1978 he also decided to create a working exhibit dedicated to the art of lambic brewing. Opening Cantillon to the public allowed them to bring some extra revenue to help balance the books. It also helped to spread the word to both locals and to tourists.<ref name=“GeuzeKriek”>Jef Van den Steen, [[Books#Geuze & Kriek: The Secret of Lambic Beer|Geuze & Kriek: The Secret of Lambic Beer]], 2012</ref>
Sales began to increase. Jean-Pierre continued to take steps to increase quality control, including discontinuing sales to stores that stored the beer upright. Storing the bottles upright caused the cork to dry out and let all the carbonation out. Jean-Pierre eventually brought his son, Jean, into the business in 1989. Like his father, who had no formal brewing experience before working at the brewery, Jean Van Roy learned lambic on the job. With the lambic industry as a whole turning around, Van Roy began to pay off the past debts to the Cantillon family and by 1992 fully owned the brewery.