Wide selection of rim sizes and tolerance requirements.Application Based Sieve Packages. Hard to find sieves

BRASS RIM SIEVES FOR USE WITH THE COFFEE

STAINLESS STEEL RIM SIEVES

COFFEE GRIND SIEVES

Conducting a particle size distribution test on coffee grinds, provides useful information, not only as to whether a grinder is operating as it should, but

also on how a cup of coffee will taste.

The rule of thumb, is that the smaller the particle, the more surface area exposed, the less contact time with hot water.

A sieve test is carried out by placing brass (less expensive-less durable), or stainless steel rimmed sieves, with differently sized wire mesh bottoms, in a stack, with the largest aperture mesh on top, and the smallest apertures on the bottom. As the nest is agitated (See Sieve Shakers) , coffee grinds will fall through the nest of sieves, and be retained by the apertures that are two small for it to pass through. The amounts retained on any one sieve, are expressed as a percentage of the whole

The manufacturuing techniques and sizes are somewhat standardized, using ASTM Sieve Numerical Designations #12, #16, # 18, #20, #30, #40, and #50, at least as a starting point.

Some of the older studies reference Tyler Sieve Designations, which were developed by WS Tyler, a sieve manufacturer, prior to the development of the ASTM & ISO Standards in use today. The numbers used are similar, but not the same. Therefore it is always important to specify ASTM or ISO, as well as verify

the millimeter equivelants.

SCREENS FOR COFFEE BEAN SIZE GRADING

As part of the grading of coffee beans, size and density are two important considerations. Agricultural grading sieves are made by perforating a steel plate with round hole apertures in 64th" increments. They are available in 8" round stainless steel rims for use with a sieve shaker, or by hand, and 12" square wooden frames for sieving by hand. There is a special wooden sieve shaker, available to hold wooden sieves, although we recommend a standard sieve shaker and sieves designed in accordance with ASTM E-11, for mechanical sieving. Many QC Labs simply have wooden hand screens, but in order to achieve an accurate endpoint, the official procedure is to verify that the amount retained on any one sieve changes less than 1% (.1% for audit purposes) after one additional minute of sieving. Because of the subjective nature of hand sieving, it is difficult to obtain repeatible accuracy. Never the less, it is better to have something instead of nothing, and if careful attention is paid to the methodology, useable results may be obtained from hand sieving.

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PROFESSIONAL LABORATORY INSTRUMENTATION FOR COFFEE, TEA, COCOA AND AGRICULTURE

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-Manufactured in accordance with ASTM Specifications

-Same as ASTM COMPLIANT, but including a signed mesh inspection certificate.

- Same as certified, but manufactured with 50% (MIDPOINT)

less tolorence than specified by ASTM E-11

APPLICABLE SIEVE TYPES

In order to calculate density, you simply divide the weight of the sample by the volume. So you need something that measures volume, like the SINAR BULK DENSITY CYLINDER, which measures exactly 1/3 liter, and a scale. In agricultural applications, the results are normally displayed in kilograms per hectoliter, or pounds per bushel, so you may have to do a little math.

SEE ALSO CERTIFIED PORTABLE COFFEE SIEVING KIT

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Weems Va 22576

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