Unbleached coffee filters - history
On 8th July 1908 the first paper coffee filter was invented by German housewife Melitta Bentz. She wanted to remove the bitter taste caused by boiling loose grounds or using the typical method of linen to brew coffee. She patented her invention and formed a company to sell the coffee filters, hiring her husband and two sons to assist her as the first employees.
Unbleached coffee filters – how are they made?
The raw material (pulp) for unbleached coffee filters are coarse long fibres, often from fast growing trees. Typically, Unbleached coffee filters are made up of filaments approximately 20 micrometres wide, which allow particles through that are less than approximately 10 to 15 micrometres.
Unbleached coffee filters - sizes
For a filter to be compatible with a coffee machine the filter needs to be the correct shape and size.
Cone shaped unbleached coffee filters are available in the following sizes:
Size 2 or 1x2
Size 4 or 1x4
Size 6 or 1x6
Size 102 or size 3
Unbleached coffee filters - Important factors to consider
Important factors to consider when choosing unbleached coffee filters are strength, compatibility, efficiency and capacity.
If coffee filter paper doesn't possess enough strength, it will tear or rupture, allowing coffee grains to collect in the coffee pot.
Compatibility describes a coffee filter paper’s resistance to degradation by heat and chemical attack; a filter that is not compatible with the liquid passing through it is likely to break down, losing strength (structural failure).
Efficiency is the retention of particles in a target (size) category. The efficiency is dictated by the particles or substances to be removed. A large-mesh filter may be efficient at retaining large particles, but inefficient at retaining small particles.
Capacity is the ability to retain previously removed particles while allowing further flow. A very efficient coffee filter paper may have a poor capacity causing increased resistance to flow as it is plugged up prematurely increasing resistance and causing poor drainage. A balance between particle capture and flow requirements is required.