Update April 2016    dissolvedgas.com

Trace Measurement Ltd


DO analysers (ppb levels)

Traditionally these were calibrated in air (9000 ppb @ 20°C) and the zero was tested either in sodium sulphite solution or pure Nitrogen / Carbon Dioxide

(It was once claimed that you could test your zero in old beer but  nowadays it is regarded as a very poor test)

A major problem is that checking the span at 9000 ppb is far from the DO levels seen in beer (< 50ppb)

Using special gases that have low levels of O2 as verification requires time for stabilisation. Bio-films (wild yeasts) readily grow on sensors, causing th e analyser to read low (membrane or fluorescence type),  however in a dry reference gas the bio-film O2 absorption is different to when it is wet, hence the test can be incorrect

Reference water in cans should provide a better way as it is a liquid like beer, however reference water has long been known to be extremely difficult to make and is often very inconsistent - you need perfect packages (because they are sitting in air that contains 21% Oxygen) and you need perfect packaging methods to make consistent reference water samples.

Verifiers give you reference water that is totally reliable and instantly available.

With verifiers you get  instant answers without any dismantling and the analyser sensor is kept clean

DO analysers (ppm levels in Wort)

Whilst it is common to have mass flow controllers and in-line DO analysers it is still necessary to have portable analysers to check that the in-line devices are working correctly.

Checking wort oxygen levels is critical to many brewers but can be very difficult


CO2 and N2 analysers

Verifiers allow instant testing of all types of CO2 and Nitrogen analysers without having to pass gases through the units or dismantling flow cells

Analyser  servicing

Traditionally analysers were serviced on a time-based method (eg. change a membrane every month).

All time based methods are inefficient at best or just wrong!

At the monthly service either the analyser is working correctly so servicing it is just a waste of time or else it has already failed, which means you have no idea how many incorrect results there have been since the last service.

Brewers who use verifiers only need to service their analysers when they go wrong  

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