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How to fix Stuck and Sluggish Fermentations

Stuck and sluggish fermentations can be a major concern during vintage and, in the worst cases, lead to irreversible wine spoilage. Problem fermentations are now better understood, which makes it possible to use prevention tools such as selected yeast strains, yeast hulls and winemaking practices.

Restarting stuck ferments with Fermichamp yeast

Stuck and sluggish fermentations are unpredictable and restart procedures are often difficult. The usual ratio of fructose to glucose in grape juice is typically 1:1, however in a sluggish or stuck ferment this ratio can increase up to 20:1 and the ferment can be difficult to restart without the addition of a fructophilic yeast, such as Fermichamp.

Able to metabolize fructose in high alcohol conditions, Fermivin Champion (previously known as Fermichamp) is the ideal yeast for problem fermentations. It can be used as both a treatment and in the prevention of stuck ferment by adding it at the end of fermentation to a potentially high alcohol must (up to 17%).

Used as a treatment, Fermivin Champion (previously known as Fermichamp) restarts stuck fermentations and allows complete sugar consumption providing slow, steady kinetics after restarting. It consumes 16.5 grams of sugar to produce 1% alcohol under optimum temperature range of 15 to 30 °C.

Using Fermivin Champion (previously known as Fermichamp), the average volatile acidity production is generally less than 0.3 g/l and both H2S and SO2 production are extremely low. One of the great benefits of using Fermivin Champion is that it preserves the specific characteristics of the must when restarting fermentation, without producing secondary aromas.

Figure: Comparison of the efficiency of 4 yeast strains used to restart fermentation on a Chardonnay must

 

 

Must detoxification with Extraferm yeast hulls

During fermentation, wine yeasts produce several compounds such as medium length chain saturated fatty acids which inhibit sugar transport. The objective of must detoxification is to remove these compounds and create more favourable conditions for yeast growth activity.

By removing toxic compounds Extraferm improves fermentation conditions, thus improving yeast performance. Therefore Extraferm helps to allow complete fermentation.

Testing for glucose and fructose

It is helpful to know the sugar content of the ferment so that you can tackle it most effectively. Individual sugar contents can be determined using the Vintessential Glucose & Fructose enzymatic test kits with a spectrophotometer, which allows quick and accurate determination of these individual sugars separately, or as a total.

Our range of Glucose & Fructose kits include:

For those not yet set up for enzymatic analysis in their lab, you can send your samples to your closest Vintessential lab for fast turnaround analysis of Glucose and Fructose. For no extra charge, we can provide at your request separate figures for glucose and fructose.