When scientists working at FOSS on analytical solutions for the dairy industry developed a breakthrough in analysis of liquid samples, they were quick to see the potential for other applications. “The original solution was for milk, but we called it a liquid product analyzer, because we could see how it could be used beyond the dairy industry,” explains Henrik Juhl, who has followed the development of liquid analysis from the original concept in the late nineteen nineties to the current day.
Instant insights with infrared
The innovation came through the use of infrared light to look deep into the composition of a liquid sample, right down to the molecular activity in fact because this is where a treasure trove of knowledge is waiting to be found.
All organic molecules vibrate and this vibration can be seen by shining infrared light through a sample and detecting what comes out the other side. This creates a signal in the form of an infrared spectrum that reveals all sorts of interesting things about the sample. “The analysis is based on infrared transmission,” says Henrik. “You send light in and then you collect light on the other side to obtain the spectra. The spectra can then be converted into useable data.”
Having cracked the code for applications for testing dairy products, the developers were quick to see the potential for wine. Instead of looking for molecular vibrations indicating fat and protein in milk, why not get the technology to look for ethanol, pH, malic acid and others in a sample of wine? This could open-up a new world of insight for winemakers. Test results for several parameters could be delivered in seconds, much faster than the traditional test methods.
Collaboration from concept to practical solution
Having established the concept, work began on making an analyzer that would be easy and practical to use for wine laboratories and winemakers as part of their daily work. This led to the first FOSS WineScan™ analyzer launched in 1999 and a raft of further evolutionary steps up to the present day, each providing incremental gains in terms of capability, ease of use and cost of ownership.
While the development of the instrumentation went quite quickly, the biggest step was to create the mathematical models that could convert the infrared signals into meaningful data. “It was a trial period,” explains Henrik. “It was really a case of finding out what we could measure and what we could not.” This is where a key aspect of the WineScan technology came into play.
What’s your wavelength?
Compared to earlier analytical technology that only used certain parts of the mid-infrared wavelength, it exploits the full range. This can be likened to standing on a hilltop with a nice view across a broad horizon. You can see a whole lot more than if you are down in a valley full of trees.
Nonetheless, the definition of what can be seen with mid-infrared analysis, has limitations. “All molecules contribute to the mid-IR spectra, but their contribution is proportional to their concentration,” says Henrik. “If their concentration is too low it goes below the threshold of the instrument. For instance, when you go below 0.5 grams per litre, it becomes very difficult to measure.”
An ongoing collaboration with the industry played an important part in the voyage of discovery. “There was a lot of interest from wine labs and a very good collaboration,” says Henrik. “When they tested a sample with the standard reference methods, they also tested on the WineScan instrument to capture spectra.”
The recording from both reference tests and from the infrared analysis created a rapidly growing pool of data that was used to find out just what parameters could be measured and to program the solution accordingly.
The first tests provided were for ethanol, pH, volatile acid, total acidity, malic acid, lactic acid, glucose and fructose.
As valuable and groundbreaking this was, the wine industry was quick to point out that the number one parameter of interest in finished wine was still missing from the list, namely the need to test sulfite in the form of free and total sulphur dioxide. “The most important one and measured again and again is SO2,” Henrik explains and continues: “As it is consumed by the wine, it is important to measure frequently to check that you still have some left to retain its preservative action, but no one wants to add more than needed.”
The problem with SO2 for the original solution was that the concentration is very low. Henrik and his team had to accept that it could not be included in the first solution offering. “But we did not give up,” he says.
Ideal for liquids
Positive feedback on the first solutions in France and Spain spurred on the developers to meet an ever-growing wish list of important test parameters. The development of tests for grape must was a particular priority, as it could make a big difference to the assessment of grape quality during the busy harvest period. More insight into parameters such as glycerol, gluconic acid and acetic acid would allow better decision making about handling grapes for best results downstream in the winemaking process.
The development required work on sample handling. With mid infrared analysis, the light can only penetrate a very thin liquid sample of about half the thickness of a piece of paper, or 50 micron, to be precise. This places certain restrictions on the sample type and how it is presented.
In the meantime, the calls for SO2 only grew louder until a game changer was found. “We discovered that the SO2 can be measured with the mid-IR technology, if you can transfer the sample from a liquid into a gas phase, so we did that,” Henrik describes. “It was a challenge, but we did it.”
He explains, how a big part of the challenge is that a liquid sample of wine contains around 85% percent water. “It absorbs a lot of infrared light, which becomes a problem, when you want to measure low concentration parameters such as SO2. But if you are able to create a gas, you can reduce the amount of water in the gas phase and adding acid into a sample, you can evaporate the SO2, so you are seeing much more SO2 and much less water.”
Perfecting a proven concept
Further milestones along the wine analysis highway have included instruments working on the same technology, but with a smaller physical and economical footprint for smaller wine producers. Just one of the neat things that had come out of this, is a way to handle sparkling wine without sample preparation. Normally, the sample must be degassed to remove bubbles, as these would simply allow the light to pass straight through without registering a signal.
Bringing things right up to date, the latest WineScan platform returned to the SO2 challenge to take it to the next level with ease of ownership, improvements with UV light, rather than Infrared for detecting the SO2. “We have pretty much figured out, what we can and can’t measure,” says Henrik. But he also points out that the work to raise rapid wine analysis to ever higher standards around the globe, will never stop. “We are not selling instruments, but results that empower winemakers and wine laboratories to do a better job. That requires translation to local area variations in the form of a calibration that works wherever wine is made. We have been successful in re-using the calibration work for the earlier solutions and transferring them to the new, and in that way the new solutions are getting stronger and stronger,” Henrik concludes.
