Page "Labor theory of value" Paragraph 23

Consider for example workers who take coffee beans, use a roaster to roast them, and then use a brewer to brew and dispense a fresh cup of coffee.

In performing this labor, these workers add value to the coffee beans and water that comprise the material ingredients of a cup of coffee.

The worker also transfers the value of constant capital — the value of the beans ; some specific depreciated value of the roaster and the brewer ; and the value of the cup — to the value of the final cup of coffee.

Again, on average the worker can transfer no more than the value of these means of labor previously possessed to the finished cup of coffee So the value of coffee produced in a day equals the sum of both the value of the means of labor — this constant capital — and the value newly added by the worker in proportion to the duration and intensity of their work.