Fermentation Wine Consultant (FWC)
Another challenge in tracking fermentations the old fashioned way is that even if you have an accurate cell count it takes many years of experience to interpret the value and correlate it with temperature, pH and density.
Oculyze’s FWC cloud based Artificial Intelligence (AI) models bundle years of research and must related data to give the wine maker a tool that not only provides raw data about yeast but puts it in context of the fermentation – just like a consultant would.
FWC enables wine makers to quickly interpret the results of their cell counts by means of warnings if something seems to be off. They no longer need 20 years of experience to know what the cell concentration means for them, they now have a tool in their hand to prevent stuck fermentations.
You can’t control the weather but with FWC you can control your fermentations. You can order the FWC-addon to your Fermentation Wine cell counter here.
Stuck or sluggish fermentation affect
up to 20% of the global wine fermentations
Stuck or sluggish fermentations occur in the cellar. The yeast struggle to convert sugar to alcohol and carbon dioxide (sluggish) or become completely dormant (stuck).
This can cause a myriad of problems:
Bacteria can take over the fermentation, resulting in off-flavors
A wine destined for dryness will not be able to finish fermentation without adding additional yeast, leaving residual sugar and leading to undesirable sweetness
Oxidation, resulting in off-flavors
Dead yeast/autolysis and the consequent off-flavors
It can occur for a number of reasons including:
Insufficient living yeast cells at the start of fermentation
Insufficient nutrients (e.g., nitrogen deficiency)
Poor inoculation technique
Lack of oxygen at the start of fermentation
Sugar levels are too high
Alcohol level is too high
Temperature too cold or too hot
pH is too low
Biochemical communication: bacteria affecting yeasts’ ability to consume sugar
Prevent stuck fermentations
To prevent stalled or stuck fermentations and avoid risking the contents of an entire tank or vintage it is fundamental to control the fermentation on a daily basis. Commonly this is done by refractometers and density meters. The challenge with these methods is that density follows the metabolic activity of yeast and if you wait for your sugar content to deviate from your expectations your fermentation is already sluggish if not stuck. By means of a microscope, counting chamber and staining agent you can keep an eye on your yeast population, allowing you to react early to fermentation problems- if you are experienced enough to spot them. Determining concentration and viability requires a lot of practice There is quite a bit of subjectivity involved when it comes to counting cells and determining viability. Which is why the analysis should be conducted by the same person every time. One of the main reasons wine makers stop doing this time consuming analysis is that the manual measurements vary so much that the results cannot be trusted from one measurement to the next- let alone from one year to another. This problem can be solved by automated cell counters for yeast but besides being expensive they are not desinged with wine makers in mind. Do to its very rich microbiologial diversity wine fermentations are particularly interesting and challenging.
Figure: Example comparison of stuck and normal fermentation and problem detection time frame by method
Figure 1 shows 2 yeast concentration curves (orange and dotted orange) and two density curves (blue and dotted blue). While the dotted lines show how a normal fermentation without problems would have developed, the colored lines show a stuck fermentation. Starting from day 3 onwards problems with the yeast become visible via the Oculyze FWC (magenta bar), around day 7 these problems can be detected via traditional density meters (grey bar). Using Oculyze FWC the problem will be detected up to 6 days earlier than by only analyzing the density. The FWC prediction models use a combination of yeast parameters including viability (not shown in the graph above), as well as the density readings.
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