Vegetable shortening is a solid fat made from hydrogenated vegetable oils, manufactured to have a bland flavour and a firm, workable texture for baking and frying. Hydrogenation — adding hydrogen to liquid oils — raises the melting point and improves keeping quality, which is why shortening gives pie crusts their flakiness and keeps cakes tender: the solid fat coats flour particles and inhibits gluten. Traditional shortenings contained significant trans fats from partial hydrogenation; modern versions use fully hydrogenated or interesterified oils to avoid them. It is 100 percent fat with no water, unlike butter, so recipes need adjustment when substituting. Its neutrality is its purpose — structure without flavour.