Fermentation Basics
Tepache, tejuino and ginger beer are short, living ferments. Hygiene, temperature, acidity and time decide whether the result is delicious or dangerous.
Mexican ferments and a classic
Tepache: pineapple rind and core with piloncillo, cinnamon and water, fermented a few days. Tejuino: nixtamalized corn masa cooked with piloncillo and fermented; served with lime, salt and sometimes lime sorbet.
Ginger beer: ginger, sugar and water with a culture (ginger bug or yeast). It's bottled to build natural carbonation, which demands pressure control.
Hygiene, temperature and pH
Wash and sanitize jars, tools and hands. Use potable water and sound fruit. A mild room temperature, roughly 20–26 °C, gives predictable ferments; heat speeds everything up.
A healthy ferment acidifies. Measuring pH with strips or a meter gives you control: look for it to drop clearly below 4.6, the usual safety threshold, and usually well below in an active ferment.
Signs of spoilage
Bubbles, a sour fruity aroma and some cloudiness are normal. Some signs are not.
- Fuzzy or colored mold (green, black, pink, blue).
- Slimy or stringy texture.
- Putrid, harsh solvent or garbage smells.
- pH that won't drop, or strange colors.
Pressure in bottles
A sealed ferment keeps producing CO₂. A sealed bottle can build enough pressure to burst, especially if it's glass or warm.
Use a PET control bottle to feel the pressure, burp bottles daily and refrigerate as soon as they're ready: cold slows fermentation but doesn't fully stop it.
Equipment
- Wide-mouth glass jars
- Breathable cloth cover or airlock lid
- Food-safe sanitizer
- pH strips or meter
- Thermometer
- PET bottles for bottling and pressure checks
Key variables
- Temperature
- Roughly 20–26 °C. More heat = faster, less controllable fermentation.
- Time
- Tepache and tejuino are often ready in one to three days; taste daily.
- pH
- It should drop clearly below 4.6. If it doesn't, discard.
- Sugar
- More sugar feeds more fermentation, more gas and some alcohol.
Process
- 1
Clean and sanitize all equipment and the work surface.
- 2
Prepare the base (pineapple with piloncillo, cooked masa with piloncillo, or ginger with sugar) using potable water.
- 3
Cover with cloth or an airlock lid and leave somewhere mild, out of direct sun.
- 4
Check and taste daily; measure pH and log it.
- 5
When flavor and acidity are right (usually one to a few days), strain.
- 6
Bottle if you want carbonation, with a PET control bottle; burp daily.
- 7
Refrigerate, label with date and use soon.
Storage
Always refrigerated once ready, in clean lidded containers or PET bottles. Label with start and bottling dates.
Shelf life
Be conservative: use within a few days refrigerated; it keeps fermenting and changing. Label and date; when in doubt, discard.
Use it in
Pulque · Blended
Pulque curado
Fresh pulque blended with fruit: thick, tangy and fruity. Pulquerías offer curados of oats, pine nut, celery, guava, strawberry and many more. Serves several people.
Zero-proof · Built
Tejuino
A fermented corn drink with piloncillo, served with lime, salt and lime sorbet. Sour, sweet and thick: a classic of Guadalajara street stands.
Zero-proof · Built
Tepache
A fermented drink of pineapple peel and piloncillo, lightly tart and only faintly alcoholic. It is sold in markets and street stands across Mexico.
Practical guide · 4 min read
Mise en Place
Everything in its place: how to set up your station so every drink comes out fast, clean and without thinking.
Practical guide · 5 min read
Cleaning and Sanitation
Good hygiene practice for a safe bar: hands, surfaces, ice and storage. Always follow your local health regulations.
Technical · 5 min read
Consistency and Quality Control
Making a drink taste the same every time takes systems: written specs, calibration, daily tasting and team feedback.
Sources
- The Art of Fermentation by Sandor Ellix Katz
- BARTENDER.MX Editorial
Updated October 20, 2026