Tequila from the Ground Up - Part IV
Part IV - Fermentation
The majority of natural aromas and flavors of tequila are created in the process of fermentation- this is where the real magic happens!
Once the cooked agave juice is extracted, it is transferred to stainless steel, concrete, or wood vats for it will ferment, generally for between three and six days. While the textbook formula for fermentation tells us that yeast eat sugar and convert it to ethyl alcohol, carbon dioxide, and heat, the empirical reality is much more complex. In reality, other alcohols as well as other compounds that create aroma and flavor - esters, aldehydes, and other substances known collectively as congeners - form and create complex bonds with one another.
Tequila producers may use commercial, proprietary or (very rarely) ambient yeast for fermentation. In open fermentation vats (still more common than closed vats), secondary and tertiary populations of yeast and other microbes also add small elements to the mix. After fermentation is complete, the resulting bittersweet agave “beer” (called mosto muerto or “dead must”) is usually about 5-6% alcohol by volume.
Everything that will be present in the silver tequila is already there in the must, even though at this point it tastes almost nothing like tequila! For that, we will need the next step….distillation.
We'll be back with Part V soon so keep checking back! Salud!