A few essential rules have to be followed. The inoculation has to be performed in a clean container, by adding in the following order: water at 37°C, the yeast booster such as Dynastart, then the Active Dry Yeast at the rate of 20 g/hl.
For example: If you have 100 kg of grapes for inoculation - you have to use 20 g of yeast. You have to rehydrate them in water in a ratio of Yeast / Water - 1:10 for example, 20 g have to be dissolved in 200 ml water.
The addition of must during this first step is to be avoided, as it would supply an acclimatized and active indigenous flora during the rehydration stage of a still vulnerable ADY. The ADY should be rehydrated for 20 minutes.
The addition of sugar at the beginning is not necessary since the yeast do not metabolize it during this phase. Some authors describe the positive effect that the addition of sugar has in maintaining the osmotic pressure of the rehydration medium. The decision regarding sugar addition will be left to the winemakers, however this addition should never be performed using fresh must.
On the other hand, a temperature difference (between the starter and the tank to be inoculated) of more than 10°C highly jeopardizes the survival and implantation of the selected yeasts. Thus, the starts temperature has to be lowered with successive must additions in order to approach or attain in the tank temperature. In any case, it is important that the total preparation duration (rehydration + must addition to decrease the inoculum temperature) does not exceed 45 minutes. Once the yeast has been inoculated into the tank, it is recommended to perform a pump-over homogenization.
To ensure a well-managed yeast inoculation, it is recommended to control the status of the implantation at, for example, the beginning, middle and end of the fermentation. A genetic method allows verification of whether the inoculated yeast has totally colonized the medium or has been contaminated by one or several other indigenous strain.