Other benefits to nitrogen flushing include adding a protective “pillow” that prevents product crumbling, as well as inhibiting mold growth.

Cannabis producers and packagers interested in an oxygen analyzer should investigate our Model Q20, which has been sold for this purpose throughout the U.S.

What should be considered when packaging coffee?

Coffee is a very complex product.  With all the aromas, flavors and roasting and packaging techniques, there are a multitude of factors that affect how the coffee tastes, and how long it remains fresh.  While we refrain from giving specific product advice, analyzing the headspace oxygen and CO2 will give you some powerful information to decide what is best for your coffee.

What determines how long coffee will last before going stale?

The shelf life of coffee is determined by a few key aspects, including exposure to air (specifically the oxygen in air), moisture, heat, and light.  The staling of coffee is caused by oxygen, but is accelerated by the other factors.  Coffee stored under nitrogen, in a cool/dry place will give you the longest shelf life.

What is the advantage to flushing with nitrogen over vacuum sealing?

Immediately after roasting, coffee begins to emit CO₂.  The off-gassing process last for days, meaning that vacuum packed coffee was not packaged immediately after roasting (otherwise the bag would inflate/explode).  So, while it is true that vacuum packing coffee will help to preserve its shelf life, it is generally accepted that M.A.P. (modified atmosphere packaged) coffee is fresher.

Let it all out…

Many coffee companies choose to have degassing valves in their packages allowing one way gas flow out of the package.  These valves serve to make sure that the package doesn’t over inflate, as well as allowing for displacement of residual oxygen.  Because of this, some roasters are interested in the CO₂ levels in their packages, while others are only concerned with the removal of oxygen.  Quantek Instruments provides analyzers to test for one or both gases.  The Q20 (handheld) and Q30 (benchtop) analyze oxygen levels, while the Model Q22 (portable) and Model Q32 (bench top) analyze both oxygen and carbon dioxide levels.

How much oxygen should remain in my coffee package?

Most of our coffee customers try to get “as little oxygen as possible” in their coffee package.  However, 2-3% seems to be the acceptable range.  “Considering that it is rec­om­mended to have no more than 3% oxy­gen con­tent in the pack­age, it is impor­tant to select wisely when pur­chas­ing and select­ing pack­ag­ing mate­ri­als and meth­ods.” ¹

¹Coffee Analysts, Coffee Packaging and Shelf life, March 29^th 2011

Sample can be manually injected into our analyzers; activating the pump is not required for analysis. This method can be used with all package testing analyzers.   In general, 10cc of sample is recommended for best results.

Detailed Background:

An internal diaphragm pump is used in many Quantek analyzers to draw sample from your package or container. The pump draws 5cc/sec and has an adjustable run-time between 2-15 seconds. For the vast majority of applications, this is sufficient.

However, some unique applications have limited headspace or work at partial pressures.  For example, withdrawing 15cc of sample from a rigid bottle containing 100cc of headspace will create a vacuum condition.  We call this “drawing on a vacuum”.

Drawing on a vacuum over thousands of samples can degrade the sensor and/or pump. The analyzer will also display an artificially low reading proportional to the decrease in pressure. Therefore, we recommend pulling sample out with a locking syringe for injection into the analyzer.

The syringe sampling method is recommended when:

1) the sample is either already under partial vacuum,
2) has such a low volume that removing sample would cause a partial vacuum, or
3) where the container is rigid and has very little flexibility (such as a 2L soda bottle filled almost to the top).

The Method:

An airtight syringe with an on/off stopcock is used to draw out the sample. There will be varying resistance to pulling the plunger back. Pull on the plunger and close the stopcock while the needle is still in the package. This picture shows the syringe with the stopcock in the “open” position:

After withdrawing the needle from the container, release the plunger, allowing it to “collapse” to atmospheric pressure. With the end of the syringe connected to the end of the analyzer’s sample probe, slowly inject the sample into the analyzer. This picture shows the syringe with the stopcock in the “locked” position:

Please contact us if you would like to explore the viability of this method with your application. This method has been successfully utilized for oxygen and / or CO2 analysis in applications such as:

• O2 and CO2 analysis in hummus packages
• O2 and CO2 analysis in salsa packages
• O2 analysis in bottles of olive oil
• O2 analysis in wine bottles with metal caps

For reliable analysis of vials with 0.5 to 5 mL of headspace, you may want to consider our Model 905V, which is engineered specifically for ultra minimum headspace applications.

The Q20 series is designed to be handheld, lightweight, and portable. It excels at spot checks and mobility.

The Q30 series is more rugged, and is built for benchtop use. Solid metal mounting plates are used to give it stability, but also add some weight – this is the preferred choice if the analyzer will be mostly stationary.

Finally the Q40 is designed to be rack mounted. For customers looking to maximize process integration, the Q40 has a convenient 2U size, and ships with ‘ears’ that makes installation a breeze.

We designed the Q20, Q30, and Q40 series with modularity in mind. Meaning that almost any combination of sensors and options can be accommodated to meet a wide variety of application needs. Send an email to sales@quantekinstruments.com and ask us to recommend the best analyzer for your project.

• Flow Rate – Process analyzers generally have a “bypass” installed to vent excess pressure to atmospheric pressure.  While this is our default configuration, this may not always be the case.  Each analyzer is customized to the needs of the application – an analyzer with a bypass installed will generally respond slower (by 5-60 seconds), but can accept higher flow rates without producing a pressure effect on the readings.
  • Analyzers with a bypass installed – these analyzers will see no pressure effect on the readings until at least 500 cc/min.  Even above that, the difference is statistically within the margin of error.  The increase in your readings at about 1000 cc/min will be about +1% of the concentration being measured; i.e. 85% Co2 will read about 85.8%
  • Analyzers with no bypass installed – these analyzers will see a pressure effect of about +3% on your readings at 1000 cc/min; i.e. 85% CO2 will read about 88%.
  • How do I know if I have a bypass? –  Please check with us if you are not sure and we can look up your specific analyzer.  Alternately, you can open the top of the analyzer and examine the plumbing arrangement.
  • Best Practice – If you are unsure of your flow rate, pass your gas flow through a flow meter before introduction to the analyzer.  Use a T-splitter if necessary to vent some of the flow to air, if that is acceptable for your application.

• Particulates – Our internal filter will remove particulates bigger than 0.45 microns which is is sufficient for most applications. However, it is best to filter your sample prior to introduction to the analyzer. Filters are very easy to replace and far less costly than contaminated sensors. Except in very specific, ultra low volume applications, filters should always be used. Filters ship with every new analyzer, and can be purchased here or by sending an email to sales@quantekinstruments.com

• Moisture – We recommend that your flow be <95% RH, non condensing.  Quantek offers drierite tubes to help mitigate small amounts of moisture. Customers with known moisture, or very high humidity should consider installing a condensing system prior to introducing the gas sample into the analyzer. The internal four layer PTFE filter will block moisture, but this should be depended upon only as a “last resort”.

• Temperature – less than 50 degrees C

• Other contaminants –  Your sample should be free of solvents, and free of dioxides that could react with water to form acidic compounds (such as NO2 and SO2).

* Process analyzers can include the Q30 and Q40 series. Of our ‘first generation’ analyzers, the Model 902P O2 CO2 analyzer, Model 905P oxygen analyzer, Model 906 CO2 analyzer, and Model 201 oxygen analyzers are considered “process.”

Airproducts MAP Gas Selector

This is especially true of welding applications.

While it’s easy to calibrate the analyzer based on the effect you see in the field, we can do it for you  before the analyzer ships, and issue a NIST traceable calibration certificate that shows the values at each CO2 concentration value, no matter the background gas.

Just in case you’re curious (as we could not find this data anywhere) we took an analyzer that was calibrated with 20% CO₂ / 80% Nitrogen and found these readings with different background gases:

20% CO₂ / 80% Ar reads about 18%  CO₂

20% CO₂ / 80% He reads about 22% CO₂