OEB 59 – Plants and Human Affairs Lab 7: Chocolate, coffee and tea These are three crops derived from tropical trees that have made their way around the world. Theobroma cacao L. is the plant from which we obtain chocolate, cocoa, and cocoa butter (the expressed oil from the seeds). Coffee beans are derived from Coffea arabica L. Leaves of Camellia sinensis (L.) Kuntze are processed for tea. One of the historical points of interest is that all of these plants were described by Carolus Linneaus. This speaks to the fact that these were well known in the mid-18th Century and were perhaps considered of primary interest in commerce. Part I: Chocolate tasting The percentages on labels of chocolate products refers to the amount of chocolate liquor – the liquid resulting from the ground cacao beans. It is not alcoholic and contains about 53% cocoa butter, the fat from the beans. Unsweetened chocolate – the chocolate liquor is allowed to harden. Used for baking. Bitter sweet chocolate (semisweet, dark chocolate) – Has at least 35% chocolate liquor, cocoa butter and sugar. Sweet chocolate – Has at least 15% chocolate liquor, cocoa butter and sugar. Milk chocolate – Milk (at least 12%) is added to at least 10% chocolate liquor and sugar. White chocolate – No chocolate liquor at all but contains 20% cocoa butter and 14% milk and also sugar. Cocoa – The fat is expelled from the chocolate liquor. After it hardens it is ground into a powder. Types of beans and their quality Forastero The most commonly grown type a mix of various genotypes. Hardy and high yielding. The African cultivars are of this type. Strong flavor but without nuance. Criollo The rarest and most expensive. Less intense is chocolate flavor and said to be "rich in secondary notes of long duration." Native to Central America and the Antilles. Trinitario A naturally occurring hybrid from Trinidad between a Criollo and a Forastero. Along with Forastero one of the most commonly cultivated forms. TO DO: Your job today is to taste and evaluate! There are several types, concentrations and origins of the chocolates provided. Sample these and note the following: Brand Cacao % Origin & cacao type Your assessment Green & Black’s White Green & Black’s Dark Chocolate Mast Brothers Dark Chocolate Divine Milk Chocolate Alter Eco Dark Cacao Taza Dark Green & Black’s 85 Icelandic Chocolate Green & Black’s 70 Whole Foods Milk Chocolate Taza Puro Taza Super Dark Chirardelli Intense Dark Lindt – sweet dark Taza, vanilla and chilis Miscellaneous, make your choice Part II: Coffee and tea There are several examples for you to sample and some "beans" for you to examine. Part III: A tour of our facilities The walk around the HUH building and the greenhouse (at the Biological Laboratories) is to highlight the botanical resources available here at Harvard University. Remember that there is also Harvard’s Arnold Arboretum. It is located in Jamaica Plain, a train ride from Cambridge on the Red and Orange Lines. At the Arboretum you will see examples of woody plants from around the world that grow out of doors in Boston’s climate. Here on Divinity Avenue are the dried plant specimens of the Gray Herbarium, wild collected material from the collections of the Arnold Arboretum, the Oakes Ames Orchid Herbarium, the Herbarium of Economic Botany, the Bailey-Wetmore Wood collections, and the Farlow Herbarium, which contains fungi, algae, bryophytes, and lichens. In all, there are about six million research collections here. This is one of the largest university associated herbaria in the world! Its origins date back to the work of Asa Gray, professor here from 1842 to 1888. The greenhouse This is located on the 6th floor of the Biological Laboratories. It is used both for research and for teaching purposes. There are some rare and exotic materials here that we will examine. TO DO: Working independently, choose a plant and write a basic description of it. Include details of leaf arrangement, bark or stem characteristics, whether it is a monocot or a dicot, leaf shape and other diagnostic features. The idea would be that you might be able to give your description of someone else and he/she could identify the plant you have described. Try to use proper terms as far as you know them. Your description here: .