PGA powder

Description:
PGA (propylene glycol alginate) powder is a specially prepared food grade propylene glycol. It is used as a beer and cider foam stabiliser. It is a food additive with E number E405. Chemically, propylene glycol alginate is an ester of alginic acid, which is derived from seaweed.

Benefits and advantages
- Protects beer foam from contaminants when pouring into dirty glasses, for example
- Improves the foam stability of beer with a naturally high level of foam inhibitors
- Improves the adhesion of the foam to the side of glass
- Improves the measured head retention value in the beer
- Check that the product is within its 'Best Before' date before use
- PGA powder solutions are temperature sensitive

Mode of action:
In principle, a molecule has both hydrophilic and hydrophobic parts, which modifies the bubble wall characteristics. PGA concentrates on the surface of the bubble with the hydrophobic end interacting with gas molecules inside the bubble and the hydrophilic part in contact with water molecules outside the bubble in the liquid that forms the bubble wall. There is less attraction between the hydrophobic groups than there is between the water molecules where the PGA dissolves, so the surface tension at the bubble surface is reduced, stabilising the foam structure.

Dosage:
1-2 g per 25 litres of beer, MUST dissolve before adding.
Do not exceed the dosage.

Instructions for use:
-Make a 2% solution, 2 g per 0.1 litre (100 ml)
-Boil the desired amount of water and cool down to between 30 and 40 degrees C.
-Dissolve the PGA in the cooled liquid, magnetic stirrer strongly recommended!
-Allow the solution to settle and use 50-100 ml for 25 litres of beer. Avoid the precipitate.
-If you make more than you need now, the rest can be stored in the fridge for up to 14 days.
-Add the beer just before bottling or pouring into kegs.