## 3 Results  
### Temperature Analysis  
Figures 8 and 9 illustrate the temporal trends of temperatures at different measurement points for the fermenter equipped with the traditional pumping-over system and the fermenter with the AMI system, respectively, along with the intervention times of the pump-diffuser unit. In both cases, probes P1, P2, and P4 are positioned at the must sampling/injection point, at the lowest point of the cooling jackets, and in the cap of grape marc, respectively, while probe P3 is located at the height of the cooling jackets, specifically at the highest point of the cooling jacket in tank A11 (traditional system) and at the lowest point of the second (upper) cooling jacket in tank A21 (AMI system). Figure 7: Energy consumption-measuring instrument used for data acquisition. Figure 8: Temperature trends over time in tank 11A (pumping-over system). Figure 9: Temperature trends over time in tank 21A (Air-Modulated Injection System). Considering that the cooling jackets are supplied with cold glycolate water through a ring system maintaining an almost constant temperature over time and between the two tanks, probe P3 does not register significant differences due to the different jacket arrangement, as the space between the two jackets in tank 21A is minimal. It can be observed that the traditional system completed fermentation with maceration of the grape marc over a total period of 10 days, during which the pumping-over system operated at regular intervals. This system was able to maintain relatively uniform must temperatures, with approximately 21 \({}^{\circ}\)C recorded by probe P1 and around 19 \({}^{\circ}\)C by probe P2 (Figure 8) during the final four days of fermentation, when the pumping-over interventions occurred at intervals slightly exceeding 8 h.  
In contrast, during the first six days, both temperature profiles exhibited oscillations of approximately 3 \({}^{\circ}\)C, with overall fluctuation ranges of 19.2-23.9 \({}^{\circ}\)C and 17.7-22.5 \({}^{\circ}\)C for probes P1 and P2, respectively, despite the average interval between successive pumping-overs being around 3.5 h. This behavior is certainly linked to the temperature fluctuations both in the must near the cooling jacket and in the grape marc cap, as indicated by probes P3 and P4, which registered variations exceeding 10 \({}^{\circ}\)C, with peak values exceeding 35 \({}^{\circ}\)C in the early days. Subsequently, while the cap temperature was cyclically and rapidly reduced due to the diffusion of cooled must drained at the temperature indicated by probe P1, the temperature of the must in the upper section, despite gradually decreasing over time, did not drop below 26 \({}^{\circ}\)C until the end of the process. Specifically, during the resting periods of the cap, its temperature (averaging around 28 \({}^{\circ}\)C) tended to increase due to the exothermic reactions of fermentation and was only reduced during the pumping-over interventions. The thermal gradient between the bottom of the fermentation tank and the cap remained high, even during the last six days of the process and the pumping-over system was unable to enhance convective movements effectively. Therefore, these findings confirm that, in the tank utilizing the pumping-over system, the region most subjected to thermal stress is the area near the grape marc cap. This limitation may influence all parameters affected by inadequate mixing. The fermentation process using the AMI system was completed in 9 days, 1 day less than the traditional system. During the first two days, the cap formation phase took place. In this case, a greater uniformity of temperatures was observed throughout the process, especially in the final days. This uniformity is likely due to the more effective action of the AMI system compared to the traditional one.