Does the size of coffee beans matter?
March 12, 2008
I would like to deliver two articles
addressing this issue. It is easy to become confused with the variety of
coffees available based on size grades. The grade depends on the
percentage of coffee that remains in a specific sieve (See table # 1 for
the more common grades in our market.). For example, Supremo coffee must
be 95% above 17 screen and 5 % between 16 and 14 screens.
The preparation of many lots of coffees based on the size of the beans have two main reasons; the first one is to ease the process of roasting by making the lot more smooth and consistent. The second one is related to consumer presentation for coffees sold as whole bean (Not ground).
I believe there are different ways to assess the size of the beans but I am familiar with one that is very technical and methodical. In order to use this procedure it is necessary to acquire a minimum set of elements such as a set of sieves, a scale, a probe grain, plastic bags and labels.
The set of sieves are usually made of straight wood with nesting frames. It is composed of a metal base with round holes consisting of different diameters. The scale is another piece of equipment necessary to measure the percentage of green beans held in each sieve after been shaken for at least two minutes. Over time you must check the size of the holes in the sieves with a perforation gauge because most green bean comes with a natural layer of wax which gets stuck all over the sieve, narrowing the holes little by little. The perforation gauge is intended to check the diameter of the holes in the sieves.
The question is how and why you pay attention to of the size of the green bean when buying? That I will answer next time.
Andres.
Table 1:
The preparation of many lots of coffees based on the size of the beans have two main reasons; the first one is to ease the process of roasting by making the lot more smooth and consistent. The second one is related to consumer presentation for coffees sold as whole bean (Not ground).
I believe there are different ways to assess the size of the beans but I am familiar with one that is very technical and methodical. In order to use this procedure it is necessary to acquire a minimum set of elements such as a set of sieves, a scale, a probe grain, plastic bags and labels.
The set of sieves are usually made of straight wood with nesting frames. It is composed of a metal base with round holes consisting of different diameters. The scale is another piece of equipment necessary to measure the percentage of green beans held in each sieve after been shaken for at least two minutes. Over time you must check the size of the holes in the sieves with a perforation gauge because most green bean comes with a natural layer of wax which gets stuck all over the sieve, narrowing the holes little by little. The perforation gauge is intended to check the diameter of the holes in the sieves.
The question is how and why you pay attention to of the size of the green bean when buying? That I will answer next time.
Andres.
Table 1:
