Changes

Turbid mashing begins with very a very thick (low water to grain ratio) and cool temperature rest compared to standard mashing. This helps the mash avoid becoming ‘set’ or solidified due to low water to grain ratio and high amount of ungelatinized raw grain traditionally used in lambic breweries.<ref name='Johnson 1918'/> Subsequent rests are achieved by the addition of near boiling water (called infusions) to raise the temperature of the mixture. The exact number of steps and target temperatures of the steps varies among different brewers, but typical steps include a beta glucan rest, a protein rest, multiple saccharification rests and a mash out. These rests are discussed further in the example mash profile below.

Turbid mashing derives its name from the cloudy or turbid wort which is drawn off at specific points during mashing process. This cloudy wort contains starches and proteins which have not been broken down by the enzymes in the mash into fermentable sugars, shorter peptides and amino acids. Turbid wort is transferred to a boiling kettle and heated to near boiling temperatures, denaturing the enzymes present in the liquid and preventing further conversion of starches or proteins. In most lambic breweries this is accomplished in a second boil kettle, but in some more modern breweries (e.g. 3 Fonteinen) where only one kettle is present, the turbid runnings are heated in the single boil kettle. Due to the starch and protein rich nature of this wort, care must be taken with this wort to avoid scorching during heating. In some breweries, kettles for turbid runnings have chains<ref name='Johnson 1918'/><ref name='Johnson 1895'/> or propellers (e.g. Cantillon) to ensure the turbid wort is mixed and does not scorch. In some breweries, especially those using older equipment, the removal or turbid runnings is also necessary to provide sufficient space for additional infusions of water to reach the remaining steps of the mash.