pH - pH is a logarithmic scale of acidity/alkalinity from 0 to 14, measuring the concentration of hydrogen ions in a solution. More acidic solutions have lower pH. More alkaline (aka: basic) solutions have higher pH. Substances that aren't acidic or alkaline (that is, neutral solutions) usually have a pH of 7. See Mash pH and Post-fermentation pH.
Polymers - a substance that has a molecular structure consisting chiefly or entirely of a large number of similar units bonded together; in brewing, concern is placed on the polysaccharides that do not get broken down enzymatically and are not consumed by yeast, hence, unfermentable dextrins.
Post-fermentation pH - During fermentation, the pH of the wort continues to drop from a range of 5.2 to 5.6 for a variety of reasons. Yeast cells take in ammonium ions (which are strongly basic) and excrete organic acids (including lactic acid). The yeast strain chosen can affect the final beer pH. Most lager beers finish at 4.2–4.6, with some ales ending as low as 3.8. See Mash pH.
Potassium Metabisulfite - used for removing chlorine and chloramine from tap water for brewing. Dosage is 0.44g per 20 gallons of water. A common form is Campden Tablets which weigh 0.59g (0.44g potassium metbisulfite and 0.15g inert tablet filler). See Removing Chlorine from Water.
PPG - points/pound/gallon, refers to the specific gravity of the wort. It is the unit for the total soluable extract of a malt's sugars (saccharides), and describes the change in specific gravity when malt is dissolved in water. PPG = gallons x points / pound of malt. When using extracts (LME/DME) 1 lb. of LME produces a light-bodied beer with an OG (original gravity) of 1.034 to 1.038 when dissolved into a gallon of water. 1 lb. of DME yields an OG of 1.040 to 1.043 per gallon. When a malt's yield is calculated at 36 points, it means the specific gravity of the wort, when 1 lb. of malt is dissolved in 1 gallon of water, the specific gravity is projected to be 1.036. The gravity is how the strength of the beer is described. Most beers have an OG of 1.035 to 1.080 ppg.
Racking - transferring the unfermented or fermented wort from one container to another, usually to minimize the trub in the final container before bottling. When racking fermented wort, either to a secondary fermenter or to bottles, care must be taken to avoid further oxygenation which will cause staling reactions at this point.
Saccharides - technical name for sugar molecules, made up of groups of 1-9 carbon atoms, as well as oxygen and hydrogen atoms. The important monosaccharides in wort include glucose (aka, dextrose), fructose, and galactose. The disaccharides include sucrose, which is table sugar (1 glucose and 1 fructose molecule), and maltose (2 glucose molecules). The important trisaccharide is maltotriose which consists of 3 glucose molecules. The primary constituents of malt sugar are maltose (45%) and maltotriose (14%), followed by glucose (8%), sucrose (6%), and fructose (2%), and various unfermentable dextrins (25%).
Saccharification - The goal of mashing is saccharification, ie., converting the starches of the grain's endosperm to fermentable sugars (saccharides), by enzyme activity (particularly amylase) that is induced by hydrolysis. The ideal temperature range for saccharification of nearly all grains is 147F-158F, where both alpha and beta amylase enzymes work best. Mashing at the lower end of that range favors the activity of beta amylase which produces more fermentable sugars, resulting in a crisper lighter beer. Mashing at the upper end of that range favors the activity of alpha amylase which produces more unfermentable sugars, resulting in a sweeter beer with more body. See Hydrolytic Enzymes.
Saccharomyces Cerevisiae - the technical name for ale yeast (Gr. saccharo – sugar, myces - fungus. L. cerevisiae – of beer), used primarily for fermenting ales, often referred to as top fermenting yeast. It is a close relative of the Saccharomyces pastorianus yeast commonly used for fermenting lagers. See Yeast Profiles.
Saccharomyces Pastorianus - the technical name for lager yeast (Gr. saccharo – sugar, myces - fungus. L. pastorianus – in honor of Louis Pasteur), used primarily for fermenting lagers, often referred to as bottom fermenting yeast. It is a close relative of the Saccharomyces cerevisiae yeast commonly used for fermenting ales. See Yeast Profiles.
Sodium [Na] - the sodium ion level in wort should be minimized within a range of 0 ppm to 100 ppm. If your source water contains more than 100 ppm, you have no choice but to dilute with distilled or RO water. At low concentrations, paired with chloride ions, sodium is said to sweeten the malt character, but at or over 150 ppm, sodium contributes a salty taste. Moreover, when paired with sulfate ions, sodium creates an unpleasant harshness, so the more sodium in your water, use less sulfate, and vice-versa. The safe rule of thumb is to minimize sodium, keeping it well below 100 ppm.
Sterols - any of various steroid alcohols widely distributed in plant and animal lipids. Sterols are vital to cell membrane structure and function. In regards to brewing, sterols are synthesized by yeast especially during the early phase of fermentation, enabling the yeast cell membranes to become permeable to wort sugars (saccharides) and nutrients for healthy cell growth and reproduction. Once the cell walls are permeable, the yeast can begin metabolizing the free amino nitrogen (FAN), sugars, and minerals (eg., calcium, magnesium, and zinc) in the wort as food.
Strike Water - the initial hot water (hot liquor) for infusion mashing, also called strike liquor. The initial strike water temperature is generally 10-15F above the target mash temperature, ie., 160-170F strike temperature to achieve 150-155F mash temperature.
Sulfate [SO4] - the sulfate ion accentuates hop assertiveness and contributes a dry, crisp palate to beer. Used in excess it tends toward harshness or saltiness. The recommended range of concentration is 50 ppm to 350 ppm. See Chloride-to-Sulfate Ratio.
Tannins - large, astringent, polyphenol compounds that can cause haze and off-flavors in beer. Tannins are found in grain husks and hop cone material. The greatest risk of tannin additions come when mashing at temperatures above 170F.
Tinseth Formula - provides a very good estimate of how many isomerized alpha acids are dissolved in a given beer, thus a good estimate of the perceived bitterness expressed in IBUs. The Tinseth Formula takes into account four variables, the weight of a given hop used, the AAUs of that hop, boil gravity, and time of boil, thus revealing the utilization factor, and finally the IBU contribution of that hop. See Calculating IBUs.
Top Fermentation - generally associated with ales, is a mode of fermentation in which the flocculating yeast rises to the surface of the fermenting wort. The yeast concerned, “ale yeast” or Saccharomyces cerevisiae, is relatively hydrophobic, such that upon flocculating it tends to seek the surface of the liquid to escape the aqueous milieu, before settling to the bottom after fermentation is complete. Top fermentations tend to be carried out at higher temperatures (61°F and higher) than bottom fermentations, although some styles of beer using top fermentations also ferment at lower temperatures than that (eg., kölsch beers). Because of the relatively high temperatures, fermentations by ale yeast strains tend to be vigorous and rapid, as short as a few days. See Bottom Fermentation, Ale, Fermentation, and Yeast.
Trub - the remains or dregs of grist and hops that fall to the bottom of the boil pot/fermenter during the beer making process, including grain hulls, coagulated proteins, hop fibers, and other solids. Exclude as much as possible before bottling. Racking to secondary containers at each step helps eliminate nearly all trub from the bottled beer. If you are really concerned about removing all traces of trub from your finished beer, bottling trub traps are available. Otherwise, many of us enjoy a trace amount of trub at the bottom of a good beer.