The figures we quote for colour and bitterness are specified for the product inside the can at the time of packaging. Of course, the product is concentrated, hence the seemingly high figures! The figures become more realistic once they are plugged into a formula for estimating the colour and bitterness of the reconstituted and fermented brew. To calculate the bitterness of the brew: multiply the quoted product bitterness by the weight of the product (1.7kg)* and divide by the total brew volume (normally 23 litres). * We use the weight because our quoted colour/bitterness figures are based on a 10% weight/volume dilution. Product bitterness x 1.7 / Brew volume = Brew Bitterness before fermentation As an example, if a brew is made with Mexican Cerveza up to a volume of 23 litres: 270 x 1.7 / 23 = 20 IBU (International Bitterness Units) This figure represents the brew bitterness prior to fermentation. Generally, fermentation reduces colour and bitterness by between 10 to 30%. So final bitterness of the fermented brew may be anything from 14 to 18 IBU. Colour may be calculated in the same way. Ensure to add the colour contribution of all ingredients together. Colour figures are quoted for liquid extract at the time of packaging as these products will darken with time. The darkening process is accelerated by exposure to elevated temperature.