## 2 Materials and Methods
### Experimental Trials  
The trials on fermenter A21 were conducted by shutting down all other compressed air users to evaluate the actual power consumption of the compressor throughout the process. Four extraction levels of compressed air were tested multiple times during fermentation: Extraction level 4, corresponding to an air flow rate of 1.1 m\({}^{3}\)/cycle; extraction level 7,  
Figure 4: Fermenter tank 21A: external compressed air pipeline (**left**) and internal view of an air injection nozzle (**right**).  
Figure 5: Fermenter tank No. 11A (traditional system). (**Left**): recessed impeller centrifugal pump; (**center**): diffuser unit; (**right**): control panel.  
corresponding to an air flow rate of 2.1 m\({}^{3}\)/cycle; and extraction level 8, corresponding to an air flow rate of 2.8 m\({}^{3}\)/cycle.  
The air injection program was structured into three phases: a series of injections every 3 h for the first 3.5 days; a series of injections every 4 h for 1 day; and a series of injections every 6 h until the end of fermentation, for a total duration of 9 days. The compressor operated autonomously to maintain the air pressure in the tank within the 4-6 bar range.  
For fermenter A11, the pumping-over program was structured into three phases: a pumping-over cycle lasting 15-20 min every 3-4 h during the first 6 days, and a pumping-over cycle lasting 10-12 min every 8 h until the end of fermentation, for a total duration of 10 days.  
The following functional parameters were determined:  
* Temperature variations inside the fermenters;
* Energy consumption of the equipment used in each cap management process;
* Total fermentation time.  
Each fermenter was equipped with four temperature probes at different heights: probe P1 at 1.5 m from the bottom (Figures 2 and 3); probe P2 at 3.6 m from the bottom, located under the cooling jacket in fermenter A11 (Figure 2) and under the lower cooling jacket in fermenter A21 (Figure 3); probe P3 at 5.4 m from the bottom, located above the cooling jacket in fermenter A11 (Figure 2) and under the upper cooling jacket in fermenter A21 (Figure 3); and probe P4 at 8.2 m from the bottom, immersed in the grape cap (Figure 6).  
The evolution of fermentation temperatures inside each fermenter was monitored using the SAEn5000 Parsec platform, a multifunctional, multiprocessor system designed for enological process control.  
To measure the active electrical power absorbed by the motors of the machines, a Power Quality Meter & Analyzer with data logger function (YOKOGAWA, model CW121) was used. This instrument allows the measurement of energy consumption for both single-phase and three-phase loads, considering the potential load imbalance on each phase. The measurements were conducted by inserting the instrument's connections into the electrical line between the control panel and the motor of the target machine (Figure 7), while also recording the actual operating time.  
Figure 6: Temperature acquisition probe P4 (Figures 2 and 3) viewed from the outside and inside.  
During the monitoring period, the energy consumption of the pumping-over system (pump and irrigator) and the winery's air compressor were recorded. Since the winery operates a centralized compressed air system, all other compressed air users were disabled during the compressor consumption measurements, leaving only fermenter A21 active. The actual operating time of the machine was recorded.  
Knowing the volume of air delivered at each extraction level in fermenter A21, the total air consumption was determined by considering the number of cycles performed at each extraction level.