Creamed mixtures are usually further leavened by a chemical leaven like baking soda. It is used in baking to leaven and acidify bread. A Eucharist without the Holy Leaven is invalid. Yeast, especially "Saccharomyces cerevisiae", is used to leaven bread, brew beer and make wine. Bark bread did not leaven as quickly as normal bread due to bark content. The production of carbon dioxide is used to leaven bread. Commercial bakers often leaven their dough with commercially produced baker's yeast. Another sacrament unique to the church is the Holy Leaven. It is an acid source for reaction with baking soda to leaven baked goods. Also, leaven symbolizes corruption and pride as leaven "puffs up". There are many prayers associated with the renewal of the Holy Leaven. The origin of the Holy Leaven supposedly goes back to the Last Supper. These include Holy Leaven (Melka) and the sign of the cross. Juries are often justified because they leaven the law with community norms. The program became inundated with sentiment, and it did little to leaven that tide.