Can I add more yeast to wine?

In this short article we will answer the question “can I add more yeast to wine?” with an in-depth analysis of adding more yeast to wine, what’s the difference between wine yeast and regular yeast, how to add yeast to wine, and the advantages and disadvantages of wine methods.

Wine has rarely accounted for more than 2% of UK merchandise imports, and since World War I it has averaged just 0.5%. Also, prior to 1950 wine rarely accounted for more than 4% of the volume of alcohol consumed in the UK (1).

Can I add more yeast to wine?

No, we cannot add additional yeast in winemaking, only a limited amount of yeast is permitted. Limited yeast is vital in the process of winemaking. It helps during fermentation by converting the sugar in grapes to alcohol.

Once the wine has effectively fermented there is no need to add additional yeast to the wine. Moreover, the wine yeast which was initially added at the start multiplies during the process of fermentation.

In modern, large-scale wineries, in which rapid and reliable fermentations are essential for consistent wine flavor and predictable quality, specially selected starter culture strains of S. cerevisiae with known ability are used. In addition to the primary function of these active dried wine-yeast starter culture strains to catalyze the rapid, efficient and complete conversion of grape sugars (glucose and fructose) to alcohol without the development of off-flavors, today’s pioneering winemakers demand starter culture strains with a whole range of specialized properties that can add value to the final product (2).

What’s the difference between wine yeast and regular yeast?

The vital difference between wine yeast and the yeast used in bread baking is that wine yeast is used to obtain higher alcohol levels than bread yeast, which means less carbon dioxide gas. Optimal conversion of carbohydrates to ethanol requires cells that are tolerant of high concentrations of both and able to efficiently produce ethanol at relatively high temperatures (3). In addition to that, the other difference is that while fermenting, wine yeast clears rapidly and foams less than bread yeast. Wine yeast is also more tolerant to sodium metabisulfite, which is regularly used in the making of wine. Baker’s yeast are also more adapted to cell survival and thus fermentation ability after freezing stress, for dough storage and are resistant to salt toxicity (4).

What happens if a winemaker adds too much yeast? 

During winemaking, yeast converts to sugar in grapes for the fermentation process. When extra yeast is added then the yeasts will not have any sugar to consume. This as a result will end up dying and settling to the bottom, along with the remaining lees and sediment. A winemaker would need to remove this extra sediment so that the wine is not misty and no unexpected secondary fermentation starts. 

In the US and many countries, there are legal rules and laws that how much yeast can be added to wine so that fermentation is healthy. One of the biggest reasons it is controlled is because if too many nutrients are added it can create an organic compound which is dangerous for human health.

Although there is not an official rule for the addition of yeast, to ensure the rapid onset of fermentation, the yeast population in the must at inoculation should be 5 million cells/ mL. In a high sugar or difficult to ferment must, inoculating the must with even higher populations should be considered (5).

How can we Add limited Yeast To A Wine?

Wine yeast is an important ingredient while making wine. Wine yeast is helpful in the consumption of the sugars in the wine and changes them into alcohol and CO2 gas. Wine cannot be prepared without yeast. 

In spontaneous fermentations, there is a progressive growth pattern of indigenous yeasts originating from the surfaces of grape berries and the winery equipment. The latter stages of spontaneous wine fermentations are invariably dominated by the alcohol-tolerant strains of S. cerevisiae, which is therefore known universally as the ‘wine yeast’. However, spontaneous fermentations are usually protracted and the outcome is highly unpredictable. Most of industrial wine production uses inoculated yeast (2).

There are 3 methods to add yeast to wine. Below is the method used for adding yeast in wine:

 Add The Yeast Directly To The Wine :

 This is the most common method. Firstly, open the packet of wine yeast and sprinkle it on the wine. It will automatically start dissolving in the vine. The noticeable advantage of this method is that it is effortless. The disadvantage is that some of the yeast’s ability to ferment successfully is lost at the very start of fermentation. This results in a delay of 3 or 4 hours.

 Rehydrate The Yeast. Then Add To The Wine Must:

 

The packet’s yeast is always dehydrated so we have to re-hydrate by adding water to the yeast. With this method when yeast is added to wine, the fermentation will start immediately. This method works effectively if we follow accurately the required time or temperature. Because if we do not measure temperature or leave the yeast for a longer period it will kill most or all of the wine yeast.

 Make A Yeast Starter. Then Add To The Wine Must:

 This method is often considered similar to rehydration, but it is not. IN re-hydration we get back yeast by adding a small amount of water but in this method, we add the yeast on a small amount of wine must, and then after some time, it is added into all the wine must. It is added to the entire wine after 2 or 3 days.

The advantage of this method is that it is more quickly and efficiently fragmented. In this method, yeast will be under a bit of stress, so there is very little chance of the yeast producing any off-flavors. The disadvantage is that it required more effort and time since the starter preparation takes at least 2 or 3 days before mixing it will the entire wine 

It is a personal choice which method they can use for winemaking. Each method has its advantages and disadvantages, and each method’s result is perfectly fine. 

Other FAQs about Yeast that you may be interested in.

Does Nutritional Yeast Have MSG

What is the best temperature for yeast?

Can you eat nutritional yeast raw?

Conclusion:

In this short article we have answered the question “can I add more yeast to wine?” with an in-depth analysis of adding more yeast to wine, what’s the difference between wine yeast and regular yeast, how to add yeast to wine with the advantages and disadvantages of wine methods.

References:

  1. Anderson, Kym, and Glyn Wittwer. UK and global wine markets by 2025, and implications of Brexit. J Wine Econ, 2017, 12, 221-251.
  2. Pretorius, Isak S., and Florian F. Bauer. Meeting the consumer challenge through genetically customized wine-yeast strains. Trend biotechnol, 2022, 20, 426-432.  
  3. Benítez, Tahía, et al. Selection of wine yeasts for growth and fermentation in the presence of ethanol and sucrose. Appl Environ Microb, 1983, 45, 1429-1436.
  4. Lahue C, Madden AA, Dunn RR, Smukowski Heil C. History and Domestication of Saccharomyces cerevisiae in Bread Baking. Front Genet. 2020, 11, 584718.
  5. Dharmadhikari, M. Wine Yeast. Midwest Grape and Wine Industry Institute. 2016. Iowa State University.