The cellulose acetate pull in a filter is a net of fibres made from wood pulp. During producing, the filter material comes as a single long piece of over 10,000 fibres pushed into large 750 kg bales.
In a filter maker, this piece of small fibres is mechanically extended to open the fibres up, dispersed with a plasticizer to join them together, covered with thin paper, cut, and fed into a cigarette-making machine.
Varying the taste and smoke yield
When the taste has been established, other design characteristics can differ the strength of the taste, and can lower the yields of different smoke elements, as scored by a standardised machine process.
The design of the filter can be different, for instance by making holes, by modifying its length or its density, by the fineness of the fibres and by the sort of material used. All these filter versions can have an effect on the level of filtration, and thus the taste, smoking experience and smoke yields as tested by a standardised machine method.
Charcoal is sometimes joined with the regular cellulose acetate, as its adsorption features can minimize some of the gas elements in smoke. It is commonly used in a filter with two sections: a plain white cellulose acetate part at the mouth end and a part that has been scattered with charcoal. Because charcoal is primarily elemental carbon, these are sometimes called carbon filters.
Making small holes in the filter is called filter ventilation, to minimize a cigarette’s yield and sensory strength. These dilute the smoke with air, resulting in less smoke being released in each puff. Filter ventilation is essential in lowering smoke gases that are not trapped in the filter.
The paper around the tobacco rod and around the filtration zone can be modified. The porosity of the paper (the amount of air that can pass through it) will have an effect on the yield, strength and taste of the cigarette. The more air that can go through the paper, the more the smoke constituents passing through the cigarette are diluted, to make a lower yield, lighter tasting product.
Another design characteristic to change the taste, strength and delivery of smoke constituents is the use of extended tobacco lamina, known as Dry Ice Expanded Tobacco. This is tobacco lamina that has been puffed-up and expanded.
As expanded tobacco takes up much more volume than ordinary tobacco lamina, less tobacco is needed to make the cigarette, leading to a different taste and lower emissions, including of tar.
Putting it all together
In producing, each cigarette brand has a particular tobacco recipe, a designated paper, filter, level of filter ventilation, tipping and graphic printing.
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