LACTOSE - An unfermentable disaccharide.
LAGER - A generic term for any beer produced by bottom fermentation, traditionally by decoction mashing, as opposed to top-fermented beer produced by infusion mashing, called ales.
LAGERING - After primary fermentation the lager beer is stored in cold cellars at near-zero temperatures for periods of time ranging from a few weeks to several months for maturing and clarification.
LAGER YEAST - It is also known as ''bottom-fermenting yeast (Saccharomyces pastorianus) because of its tendency not to flocculate, or form a head of yeast on the surface of the brew.
LAUTER TUN - A vessel fitted with a false slotted bottom equipped with a sparging (hot water delivery) system to wash the mash to recover the extract. Unlike mash tuns they are wider and shallower and are equipped with rakes.
LAUTERING - Process of removing spent grains or hops from the wort. This is simply done by the utilization of a strainer and a subsequent quick, hot water rinse (sparging) of the caught spent grains and hops.
LIGHT STRUCK - An unpleasant flavor in beer caused by exposure to light causing undesirable chemical reactions of hydrogen sulfide and other sulfur compounds, which impart a skunk-like flavor.
LIPIDS - Lipids are fatty acids derived from yeast metabolism, oxidized hops and malt. They affect ability of beer to form a foam head and play an important role in beer staling. Lipids cause soapy flavors, and when oxidized contribute to stale flavors. On the positive side, they contribute to yeast viability.
LIQUEFACTION - The process by which alpha-amylase enzymes degrade soluble starch into dextrin.
LIQUOR - The name given, in the brewing industry, to water used for mashing and brewing.
LOVIBOND METHOD - A standard method for determining beer color used both in the United States and in Europe. It has since been replaced by the more official Standard Research Method (SRM) and the European Brewing Convention (EBC) method by the United States and the European Union, respectively. Color measured as degrees Lovibond.
LUPULIN GLANDS - The tiny yellow sacs found at the base of the petals of the hop cone. They contain the alpha acids, beta acids, and hop oils.
LUPULONE - See Beta acid.