Troubleshoot on Amasi / Maas / Mageu
WHAT IS AMASI/MAAS?
It is a cultured (fermented) full-cream milk with a thick texture and sour taste.
WHAT IS MAGEU?
It is a non-alcoholic drink made from fermented maize meal.
HOW IS AMASI MADE IN PRODUCTION?
Producers pasteurize raw cow's milk and add specific bacterial cultures like Lyofast MW035. The mixture
ferments until the pH drops to about 4.4.
HOW IS MAGEU MADE IN PRODUCTION?
Producers boil water, sugar, preservatives and maize meal to make a thin porridge. After it cools, they add wheat flour or specific
bacterial cultures and let it ferment.
WHAT IS THE SHELF LIFE OF UNOPENED COMMERCIAL AMASI?
Unopened commercial Amasi lasts up to 21 days when stored in a fridge at 4 °C.
WHAT IS THE SHELF LIFE OF UNOPENED MAGEU?
Unopened Mageu can last up to 30 days depending on the packaging and whether preservatives are used.
Protective culture can also be used instead of preservatives.
WHAT STARTS THE FERMENTATION?
Bacterial starter cultures. In milk, it is typically Lactococcus lactis. For mageu, it is lactic acid bacteria.
IS MAGEU ALCOHOLIC?
No. It only undergoes lactic acid fermentation.
WHY PASTEURIZE MILK FOR AMASI?
Pasteurization kills bad bacteria. It ensures the starter culture is the only thing growing. Also to
increase shelf life on the product.
HOW LONG DOES FERMENTATION TAKE?
Usually 12 to 16 hours for Amasi, depending on the temperature. its critical to have a consistent room temperature.
WHAT IS THE CORRECT TEMPERATURE?
Fermentation works best between 22 °C and 26 °C depending on the specific bacteria used. For Magau it is 40 °C and 42 °C.
WHAT IS BACKSLOPPING?
Using a portion of a previously fermented batch to start a new batch. Commercial plants rarely do this to maintain strict quality control. It is not advisable to do this, we prefer that a new freeze dry started culture is used for a more consistent product.
HOW ARE FLAVORS ADDED?
Fruit purees and sugars are mixed into the cooled base just before packaging. Flavor compounds
can also be used instead of puree.
WHAT IS THE IDEAL SHELF LIFE?
Commercially sealed products can last 14 to 30 days when refrigerated.
WHY IS MILK FAT CONTENT IMPORTANT?
Fat gives amasi its creamy texture. Regulations require "full-fat" amasi to have at least 3.3% milk fat. Amasi will taste better with a fat content of about 3.6.
WHAT IS A "SET" VS. "STIRRED" PRODUCT?
A "set" product ferments inside the final container. A "stirred" product ferments in a large vat and is then packaged.
HOW DOES pH AFFECT PRODUCTION?
The pH drops as the bacteria produce acid. Amasi is ready at a pH of roughly 4.5.
HOW DO YOU STOP FERMENTATION?
You lower the temperature to 4 °C to maximum 8 °C as soon as the target acidity is reached.
WHAT PACKAGING IS USED?
Polyethylene bottles, cartons, or pouches. Packaging must be airtight.
IS HYGIENE IMPORTANT?
Yes. Equipment must be cleaned with caustic agents and sterilized to prevent unwanted yeast or mold growth.
WHAT IS FORTIFICATION?
Adding vitamins or minerals to a product to make it healthier. Some commercial mageu is fortified with vitamins.
DO THESE PRODUCTS NEED COOLING?
Yes. They must be kept chilled in the factory and during transport to prevent over-fermentation.
WHAT IS GELATINIZATION?
In mageu, the maize starch is cooked in hot water to thicken it before the bacteria are added.
WHY ARE STABILIZERS USED?
Stabilizers prevent liquids from separating from the solid maize or milk over time.
WHAT IS WHEY SEPARATION (SYNERESIS)?
The liquid whey leaks out of the solid clot, making the amasi look watery. It is caused by too much acid or rough handling of the product. If too high or too low a temperature is used then whey separation will also occur.
WHAT CAUSES AN OVERLY SOUR TASTE?
What causes an overly sour taste? Fermenting for too long or storing the product at room temperature.
WHAT CAUSES OFF-FLAVORS?
Unwanted bacteria or wild yeasts growing in the production line.
HOW DO YOU FIX "GASSY" PRODUCTS?
Gas bubbles are a sign of yeast or coliform contamination. The production line needs deep cleaning and sterilization.
WHAT IS "ROPEY" MILK?
When the fermented milk becomes sticky or stringy. This is a bacterial contamination defect and the whole batch must be thrown out.
WHAT HAPPENS IF THE CULTURE DIES?
The milk will not ferment. This is caused by antibiotic residues in raw milk or sanitizers left in the vats.
CAN THESE PRODUCTS BE FROZEN?
Freezing damages the smooth texture of Amasi, though it is sometimes used for extended preservation.
HOW DOES LACTOSE INTOLERANCE WORK WITH THESE?
The bacteria break down most of the lactose during fermentation, making these products easier to digest.
WHAT ARE THE REGULATORY STANDARDS?
In South Africa, production must follow guidelines like to be safe for store shelves.
HOW DO YOU GET A THICKER TEXTURE WITHOUT STARCH?
Using specialized dairy cultures or adding skim milk powder (protein) to the milk before fermentation.
COMMON ISSUES ON AMASI/MAAS AND MAGEU
UNWANTED SEPARATION (WHEY OFF OR SYNERESIS)
Liquid separates from the thick product during storage, causing a watery layer.
Add stabilizers like gelatin, whey protein, or pectin during processing and ensure
optimal pasteurization temperatures.
BATCH-TO-BATCH TASTE AND TEXTURE DIFFERENCES
The product is too sour or not sour enough; the texture becomes too runny or too chunky.
Use commercial, standardized lactic acid bacteria starter cultures instead of relying on wild fermentation.
SPOILAGE BY MOLD AND YEAST
Visible mold growth on the surface or yeast contamination causes gassiness and fruity off-flavors.
Strictly enforce facility hygiene and package products in airtight, hermetically sealed containers.
POST ACIDIFICATION IN STORAGE
The product continues to ferment on the shelf, becoming too sour before the expiration date.
Cool the product to 15 °C immediately after fermentation, and store it consistently below 4 °C.
STARCH RETROGRADATION IN MAGEU
Mageu becomes thick and gelatinous over time, or the starch settles to the bottom of the bottle.
Use modified starches or hydrocolloids to keep the starch suspended evenly in the liquid.
CONTAMINATION BY COLIFORMS OR PATHOGENS
Harmful bacteria compromise food safety.
Pasteurize all raw milk at 72 °C for 15 seconds and strictly sanitize all production lines and packaging equipment.
CHALKY TEXTURE IN MAGEU
The drink has a rough, sandy mouthfeel.
Improve the milling process for finer maize meal and ensure complete cooking of the starches.
HIGH ENERGY COSTS FOR COOLING AND PASTEURIZATION
Refrigeration and thermal processing take a huge toll on factory budgets.
Use heat-recovery systems during pasteurization and optimize cold chain
logistics for faster chilling.
UNPREDICTABLE RAW MILK SUPPLY (DAIRY PRODUCTS)
Raw milk quality fluctuates due to weather, feed, or cow health.
Standardize the milk fat and solids-not-fat (SNF) content before
processing by adding skim milk powder.
SHORT SHELF LIFE
Products spoil quickly after leaving the factory.
Utilize strict cold-chain management and consider extended shelf-life (ESL) processing or
hot-filling (for Mageu) to prevent microbial growth.
