Yeast inoculation

Inoculation is the process of adding yeast to juice or must in order to initiate fermentation. This is often done immediately after solids separation in the case of white grape types and after vatting or cold soaking in the case of red grape varieties. It is essential to ensure that the juice or must is adequately prepared for the inoculation of the yeast culture to grow, and, as a result, the fermentation will happen.

Here we explain how to inoculate :

  • our yeasts from Anchor range,
  • our Fermivin yeasts produced in the classic way (Saccharomyces and non-Sacc.)
  • directly into the must or to grape the In-Line Ready Fermivin yeasts.

How do we proceed with rehydration and inoculation?

One of the most important steps in winemaking is yeast rehydration. It guarantees a steady and healthy fermentation. To achieve a viable yeast population of roughly 3–4 x 106 viable yeast cells per millilitre of must, the recommended inoculation dose for active dry wine yeast is 20–30 g/hL. After inoculation, there is a slight increase in yeast biomass, and fermentation starts. For more difficult fermentation conditions, higher inoculation rates are necessary.

Saccharomyces yeasts

Anchor yeasts are inoculated at 25 g/hL and classic Fermivin yeasts at 20 g/ hL.

The rehydration protocol of a Saccharomyces active dry yeast involves three main steps.

1-Rehydration:

  1. At 40 °C (104 °F), add yeast to a volume of water 10 times its weight.
  2. Dissolve 50 g/L of sugar (saccharose or must)
  3. Once the medium reaches 37 °C; add 20 to 30 g/hL of active dry yeast while actively stirring to break up any lumps. 
  4. Let the suspension sit for 20 minutes, then stir gently again. The presence of foam does not indicate the viability of the yeast. Don’t let yeast sit in rehydration water for more than 30 minutes without adding juice or must, or the number of yeast cells will decrease.

2-Acclimatisation:

  1. Slowly, over 5 minutes, add some juice or must to the yeast mixture to lower the temperature by 10 °C (18 °F). Allow it to sit for 15-20 minutes.
  2. Repeat the temperature adjustment step until the difference in temperature between the yeast mixture and the must to be inoculated is within 10 °C (18 °F).

3-Inoculation:

Add the yeast mixture right into the tank of must, ensuring you mix the yeast mixture throughout the must

Here are some recommendations:

  • Start rehydrating the yeast in a vessel that can handle up to four times the volume of rehydrated yeast.
  • For large tanks with long filling times, add the yeast mixture to the bottom of the fermenter as soon as you begin filling with must or juice. This provides the yeast with an advantage over indigenous species.

Non-Saccharomyces yeasts

The rehydration protocol of non-Saccharomyces active dry yeast differs from that of Saccharomyces cerevisiae in tiny details that are of vital importance and can only be addressed per species.

Hanseniaspora vineae (Fermivin VINEAE) requires a rehydration protocol with sugar that is not saccharose. The nature of sugar is important: all except saccharose (sucrose) are valid.

We invite you to follow our instructions described in the data sheet you find at the link here.

Using a protectant

When using a rehydrating agent like Anchor REVIVE, the yeast is added to a rehydration mixture in a volume of water that is 20 times the weight of the yeast. The rehydration agent is added to 20 times the yeast weight of water with the sugar at a temperature of 40 to 43 °C (104 to 110 °F). Then, when the temperature reaches 37 °C, you can add the yeast and follow the same protocol. 

What is the easy and direct inoculation?

Differentiation of yeast production

ILR-In-Line-Ready-fermivin

We have created a production process for dry yeasts called In-Line Ready to allow Fermivin yeast to be inoculated directly into the must or on grapes without rehydration.

Click here to learn more about In-Line Ready Fermivin yeast and its benefits.

Used extensively worldwide since 2013, In-Line Ready (ILR) yeast consistently performs well under varying conditions, showcasing its reliability across different regions.

This lowers rehydration energy costs, saves time, and avoids the specialisation and training of manpower. The inoculation is made more professional, effortless, and quicker.

The unique multiplication process enhances ILR yeast viability, making it resilient to stresses like low temperatures and acidity during direct addition.

ILR-specific production guarantees the same or even superior viability, fermentation kinetics, and wine flavour quality compared to classic Fermivin yeasts added after rehydration, providing assurance of high-quality outcomes.

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