Following info is from Nestle (about their Espresso system advertizing on the web)
It's not intended by me to say something about their espresso system or about their coffee quality. It's only intended as a contribution and general basis for different espresso blends for the homeroast group and how Nestle tries to match different tastes of customers (without AND with Robusta).
What is Robusta?
Coffea canephora, is popularly known as Robusta due to the resistant nature of its plant. Discovered by Dutch botonists in the former Belgian Congo, it was introduced in Southeast Asia in 1900 after coffee rust disease wiped out all coffee cultivation in Ceylon in 1869 and destroyed most low altitude plantations in Java in 1876. Growing as a shrub or small tree up to 10 meters in height, Robusta is self-sterile and exists in many different forms and varieties in the wild.
Cultivated in West and Central Africa, throughout Southeast Asia and to some extent in Brazil, its cross-bred varieties are often hard to identify, but two main types are generally recognized: Robusta, or up-right forms, and Nganda, or spreading forms.
Robusta fruit is rounded and takes up to 10 months to mature. Its oval shaped seeds have two sets of chromosomes and are usually unwashed, or dry-processed. Smaller than those of Coffea arabica, Robusta beans contain nearly twice as much caffeine (2-4.5% against 1.1-1.7%). Quality Markedly bitter and less aromatic than Arabica, the robust and full-bodied Robusta is widely used in blends.
The main producers and varieties include:
Africa: Ivory Coast followed by Uganda, Cameroon, Madagascar, Gabon, Angola, Zaire and other African nations.
Brazil: known as Conilon, a relatively mild Robusta.
Indonesia: Sumatra (Medan, Padang, Palembang), Bali (Buleleng), Ujung Pandang from Sulawesi (formerly Celebres), Timor and Java (Djakarta, Demarang, Surabaya) -bitter taste, sometimes fermented with consequent flavor, generally low quality.
Vietnam: a rising producer
Sources: Alain Stella, "Le Livre du Caf*", Flammarion: Paris, 1996. Philippe Jobin, "Les Caf*s Produits dans le Monde", P. Jobin & Cie: Le Havre, 1982. "Coffee", Documentation Centre, Nestec Ltd: Vevey, 1989. Sergio Michel, "The Art and Science of Espresso", CBC, Trieste, Cod. Art. 7128. ICO Fact Sheet, International Coffee Organization, London.
Their (Nestle) different blends:
Type 1 Full-bodied, the most Italian espresso. Arabica from South and Central America with a touch of African Robusta for intensity. Very long roast and very fine grind. Pronounced bitterness and strong body. Savor without stirring in a demitasse filled halfway, with or without sugar.
Type 2 The most intense, full-bodied espresso. Pure Arabica from the Grands Crus of Central America with Brazilian Santos for balance. Strong roast and fine grind. Very aromatic, full-bodied, fine bitterness, long lasting aftertaste. Enjoyed strong in a demitasse filled halfway or with a dollop of frothed milk for a "Macchiato".
Type 3 The strong, espresso of Italian "baristas". A blend of Latin American Arabica and Brazilian Santos with a touch of Central African Robusta. Long roast and fine grind. Pronounced bitterness, full-bodied, well balanced, long lasting aftertaste. Served strong in a demitasse filled halfway or as the ideal base for "Cappuccino" or "Caffe Latte".
Type 4 A satisfyingly smooth Italian espresso. Latin American Arabica and Brazilian Santos with Central African Robusta. Medium roast and medium grind. Smooth bitterness, rich body, well balanced, long lasting aftertaste. Savored in a demitasse or topped with whipped cream in a cappuccino cup for a "Viennois".
Type 5 The perfect morning espresso. Pure Arabica from the best Crus of Central and South America. Long roast and medium grind. Well balanced bitterness, fully-bodied, very fine aftertaste. Served in a demitasse or cappuccino cup, with or without milk.
Type 6 A fruity espresso appreciated throughout the day. Pure Arabica from Central America and East Africa with a touch of Brazilian Santos. Light roast and medium grind. Pronounced acididy, body, aromatic, light aftertaste. Enjoyed in a demitasse or cappuccino cup, with or without milk.
Type 7 A light and mild espresso, perfect any time of the day. Pure Arabica from Latin America. Light roast and medium grind. Delicate body, balanced bitterness and fine acidity. Served in a demitasse or cappuccino cup, with or without milk.