For the most part kits are made exactly like wine, 75% at least in the beginning.  Wine makers contract to purchase grapes from growers by specifying conditions at harvest (acid, pH, brix, and color) and organoleptic qualities (flavor and aroma).  These specifications are very rigid, for although the grapes may change radically from harvest to harvest, the kits must maintain very high levels of consistency, so consumers can make repeat purchasing decisions.  When the grapes are ripe they are harvested and taken to a winery, where they are sufited and crushed.  At this point white and red grape processing take their own course. 

 

White grapes are pressed, and the juice is pumped into a settling tank.  Enzymes are added to break down pectins and gums, which would make clearing difficult after fermentation.  Bentonite is added to the juice and re-circulated.  After several hours the circulation is shut off, and the tank is crash-chilled below freezing.  This helps precipitate grape solids, and prevent spoilage. 

 

Red grapes are crushed, sulfited and pumped through a chiller to a maceration tank, where special enzymes are added.  These break down the cellulose membrane of the grape skins, extracting color, aroma and flavor.  The tank is chilled to near freezing to prevent the must from fermenting.  After two or three days the red must is pumped off, pressed and settled much the same way as the whites.  When the tank is settled, and the juice almost clear, it is roughly filtered, the sulfite is adjusted, and it is either pumped into a tanker truck for shipment to the kit facility or into a vacuum concentrator. 

 

Vacuum concentrators work like the reverse of a pressure cooker.  By lowing the pressure inside the tank, water can be made to boil at very low temperatures.  By boiling the juice at low temperature browning and caramelization are prevented.  The water comes off as vapor, leaving behind concentrated grape juice.  Because some aromatic compounds can be carried away in this vapor, a fractional distillation apparatus on the concentrator recovers these essences, returning them to the concentrate after processing. 

 

 

 

 

The juices and concentrates are then shipped to a facility where they are pumped into nitrogen purged tanks, tested for quality and stability, and held at very low temperatures.  This both speeds up the formation of wine diamonds (crystals of potassium bitartrate from the tartaric acid naturally occurring in the wine), and preserves them until they are to be used. 

 

After the quality control checks are passed, the juices and concentrates are blended into the formulations that make up the different kits in giant blending tanks.  When the formulation is finally adjusted and approved the must is pumped through the pasteurizer.  The pasteurizer is a type of heat exchanger that rapidly heats and then cools the must, killing yeast and spoilage organisms, but not burning or caramelizing the must.  From there it goes into the bag filler which purges the sterile bags with a double flush of nitrogen, and then fills each bag to a very strict tolerance. 

 

The bags are then automatically capped and loaded into the kit boxed that come from the box former, after which the packaged additives are placed on top.  The boxes are sealed, shrink-wrapped and packed on a skid for a Quality Assurance microbiological hold. 

 

Depending on the product, this hold can be form three days to more than a week, while the product is examined for signs of bacterial or yeast activity.  If is passes, it is then shipped to the warehouse, and from there to dealers, and finally, into the hands of the wine making customer.