The winepress, (gat in Hebrew), is the area where the grapes were pressed. This was normally a limestone basin cut into the rock. Usually they were square but sometimes round...The winepress was usually close to the vineyard because there was less wastage and a greater opportunity to maintain control of the winemaking process...
Grapes would be carried in baskets and laid on the floor of the winepress, and the men usually did the pressing. This was done by treading on the grapes with bare feet. There was enough pressure to extract the juice but not enough to crush the grape pips and release unpleasant bitterness...The juice, or must (tirosh), would then flow down a gulley or channel from the main pressing area into a deeper hole, known as the yekev (literally “winery”). Twigs or thorns would be placed strategically to act as a rudimentary filter.
In the yekev, the wine would begin to ferment naturally. The natural yeasts on the skins of the grapes would find all the sugar in the grapes irresistible. The deepness of the hole and the stone surrounds would keep temperatures stable. Fermentation of the tirosh would take three to five days, and the result would be wine.
As soon as the production of carbon dioxide (a by-product of fermentation) finished and before the wine could begin to oxidize, the wine would be channeled into an even deeper pit, where Canaanite jars were filled. This was a pottery container with two large handles and a pointed bottom.
They became better known by their Greek name, amphorae. They were closed or sealed with pine resin. This imparted a unique flavor that may still be sampled in the retsina wines produced in Greece. The amphorae were stamped with seals giving the information of the vintage, vineyard, type of wine and color.
The Talmud describes 60 types of wines. Some wines were diluted with water. Others would invariably have flavors added to improve the taste and act as a preservative. Salt, seawater, herbs and spices such as cinnamon were added. Raisins or date honey were used as sweeteners. These flavored wines were forerunners of the punches or vermouths of today. Smoked wine was cooked wine. They were the forerunner of Mevushal wine, though it was done to concentrate the wine into a syrup rather than for kashrut reasons. Even in those days they knew about drying grapes on mats to concentrate the sweetness...
The Shiloh winery: