Anglo-Brazilian born in London, Frewen has been doing business in Brazil since 1986, when he had the exclusive rights to export the famous Brazilian Brahma Beer, today a key part of the world's largest brewery & beverages conglomerate. Frewen started a campaign to assist the Amazon forest with part of the beer’s revenues and was internationally awarded in several countries for this strategy as long ago as 1988.
For over thirty years he has been focused on investment and business activities with a sustainable focus, particularly sustainable organic agriculture and forestry management and reforestation projects.
He was the initiator of a project to catalogue the plants on and around the Fazenda Toucan Cipó, lasting six years, together with The Royal Botanic Gardens, Kew cataloguing over 1,200 native species within a ten mile radius. This also led to the discovery of 13 new species of plant, previously unknown to science, one of which was named after Frewen in recognition of his contribution to science: “Pilosocereus frewenii”.