It's hard to beat the aroma of fresh coffee, but retaining beans in their as-roasted condition can be challenging
One US coffee producer is using a Servomex gas analyser to help ensure its coffee is consistently good wherever it is served or sold as beans for making coffee at home.
Coffee beans quickly lose their freshness if they are exposed to oxygen; so roasted beans are packaged and sealed in carbon dioxide, sometimes with other gases present too.
However, roasted beans absorb carbon dioxide in a process referred to as drawdown, which is why coffee often appears to have been vacuum-packed.
Gas suppliers will provide a certificate of conformance stating that the composition is within the acceptable limits, and packaging machinery will be regularly tested to ensure that it is functioning correctly.
But to be certain that coffee is packed in the correct atmosphere, there is no substitute for testing.
The American coffee producer is typical in its use of a Servomex 574 portable analyser.
A number of packs of coffee are sampled per thousand produced and the oxygen concentration is checked.
This is done by using a probe that consists of a hypodermic needle, the tip of which is surrounded by a foam pad that prevents the ingress of gases from the working environment.
The needle tip pierces the pack and a small volume of gas is extracted by the analyser's internal pump (an inline filter ensures only gases are drawn into the measurement cell).
In cases where drawdown has reduced the free gas, multiple samples can be taken to provide sufficient sample volume for the analyser - though the 574 analyser can operate with as little as 2.5ml of gas.
A portable instrument can be used across several different production lines, but one of the main attractions of the 574 is its size; often the gas analyser will be vying for benchtop space with other quality assurance (QA) equipment such as weighing scales.
A portable instrument can also be carried back to a QA laboratory for recalibration if required, or the Servomex 574 can be easily recalibrated in the production environment using nitrogen and/or air to maintain its accuracy of 0.2% oxygen with a repeatability of +/-0.1% oxygen.
A further advantage of the 574 analyser is that it uses non-depleting paramagnetic technology in the sensing cell, so the operator can be certain that it will always function correctly.
In contrast, other sensing technologies can degrade, giving no indication that the readings are misleading.
In a QA application where several packs have to be tested in a short period, ease of use and speed of response are extremely important.
The Servomex 574 scores highly in both respects, plus it has an analogue output that can automatically feed data to a QA system for storage and analysis if required.
