In the previous blog, I shared with you our picking day of the Menica-our new Spanish variety. It is a fantastic opportunity to trial this grape, and with some careful monitoring we have decided to make a Rose which will go through Carbonic Maceration.
What is Carbonic Maceration?
Carbonic Maceration is often employed to make lighter reds which are fruitier and more aromatic. The region that comes to mind in Europe which is asscociated with this process is Beaujolais.
There are many variations on approaches to carbonic maceration, but I will explain it the best I can and the approach we adopted in this trial.
Carbonic Maceratiom is essentially the process that occurs when intact bunches are fermented in a sealed vessel, which is filled with carbon dioxide. For us we added dry ice (CO2 producing) to plastic sealed grapes in the picking bins.
Plastic wrapped Menica
In the absence of oxygen, these intact berries begin a intracellular fermentation process. Some alcohol is produced along with some other compounds which are great for wine flavour.
If the ferment is left long enough (eg a week or so) the berry will begin to breakdown and juice will be released. However, usually and in our case the juice was pressed out in about 3-4 days, allowing the rest of the ferment to be carried out by yeast. The result is a pale coloured red wine, with lower tannin and enhanced fruit aromatics.
Mencia free run coming out the press
Mencia continuing to ferment after it has been pressed
You want more? A brief explanation of aerobic and anaerobic fermentation
There is quite a distinction between aerobic and anaerobic respiraton – Aerobic happens in the presence of oxygen. The cells of the grape need energy and they use oxygen as its source to break down the sugar, which produces CO2, sugar and water and starts fermentation.
In the absence of oxygen, anaerobic respiration can take place in some cells. They are less able to provide the desired resulting alchohols than yeast and it needs to be monitored otherwise the berry will die if left too long.
The benefit of anaerobic respiration is that certain polyphenols (eg tannins and anthocyanins) are derieved from the pulp and skin of the berries which ulitmately turns the flesh pink. Additionally certain compounds are also produced which are important to flavour. Eg amino acids are extracted from grape solids, which also increase the nutrient state of the juices. These amino acids are also a precursor to flavour.
So in conclusion we can say that the Mencia has partially been put through Carbonic Maceration. It is important to note that as per previous blog, we did stomp a small proportion of juice before wrapping up, which would help yeast begin to thrive for aerobic respiration. The remaining intact berries begin internal fermentation-anaerobic respiration. These still have quite high sugar which post pressing keeps the ferment going. As seen in the bubbling ferment above.
So if you haven’t fallen asleep, what are we going to call the resultant Rose? Any Spanish inspired ideas people? Keep up with our blog where I will talk about colour and flavour…..as the ferment continues.
At the moment the ferment tastes of watermelon and rose petals! Pretty exciting.