Wine Analysis Home
Concentrations - % w/w, %v/v, % w/v , ppm, M, g/L
- Concentrations indicate the amount of any substance disolved in a liquid.
- Square brackets, [ ], are often used as an abreviation for the term concentration.
e.g. a 0.1 molar sodium hydroxide concentration can be refered to by [NaOH]=0.1M
- % w/w is an abbreviation for percentage weight of a substance of the total weight at a specified temperature-
e.g. 10 % w/w H2O2 = 10 g hydrogen peroxide in 90 gm (90 ml) water.
or 15 parts by weight of salt (NaCl) in 85 parts by weight of water (15% w/w) @ 12.5oC was the original definition of 15oBuame.
- %v/v is an abbreviation for percentage volume of a substance of the total volume -
e.g. 12.5 % v/v ethanol. = 12.5 ml ethanol in approx. 87.5 ml water -
Alcohol concentration is stated as ethanol as it is the predominant alcohol in wine (see ethanol equivalents)
often seen on wine labels as 12.5 % Alc.or 12.5 ALC/VOL or ALCOHOL 12.5% BY VOLUME (note the predominate alcohol in wine is ethanol)
- % w/v is an abbreviation for percentage weight of a substance of the total volume -
e.g. 18% w/v orthophosporic acid (H2PO4) = 18 g H2PO4 in a total volume of 100 ml of solution -
i.e. 18 g H2PO4 dissolved in water and topped up with water to the 100ml mark in a 100 ml volumetric flask.
( ppm, mg/L )
- ppm is an abbreviation for parts per million and is the equivelent to mg/L (more)
- g/L is an abbreviation for grams per litre, and are the units used to record wine acidity concentrations.