Lactose Powder

Lactose Powder is a refined milk sugar (a disaccharide of glucose and galactose) supplied as a free-flowing powder for use as a brewing adjunct. Unlike most sugars used in brewing, lactose is not fermentable by standard brewing yeast, which lacks the enzyme lactase required to break it down. As a result, any lactose added to the wort remains intact in the finished beer, contributing residual sweetness, body, and the characteristic silky, creamy mouthfeel associated with milk stouts and modern dessert-style beers.

This product is the defining ingredient of the milk stout style, originally developed in early 20th century England and most famously associated with Mackeson. It is added to the kettle, typically in the last 10-15 minutes of the boil, where it dissolves cleanly and is sterilised before transfer. More recently, lactose has seen a resurgence in modern hazy and dessert-style beers, including milkshake IPAs and pastry stouts, where it pairs well with high hop loads, fruit additions, and sweet adjuncts to create rounded, less astringent profiles.

Typical usage rates range from approximately 0.5-2 g per litre (around 5-10% of the grist) depending on the desired level of sweetness and body. Lactose contributes around 35-40 gravity points per pound per gallon, so additions should be accounted for in original and final gravity calculations to avoid overestimating ABV or underestimating residual extract. Restraint is important; over-dosing can lead to a cloying, syrupy character that compromises balance and drinkability. Note that beers containing lactose must be labelled as such, as it is a declarable allergen and is not suitable for vegan or lactose-intolerant consumers.