As title states, the question is can Saison yeast use lactose?

i.e. is it possible to sweeten a Saison with lactose? Or, sweeten it possibly some other way?

This is about Saison yeasts, dry or liquid.

  • 1
    Do you want to sweeten a saison?
    – chthon
    May 28 '18 at 9:47
  • Yes. I guess it could be mentioned in the question.
    – DuctTape7
    May 28 '18 at 9:51

There are yeasts which can ferment lactose, but these are not beer yeasts.

Since saison yeasts are normally single-strain beer yeasts, they lack the property to ferment lactose.

Bacteria and other wild yeasts (including brettanomyces) are able to ferment and/or metabolize lactose.


Saison yeasts do not metabolise lactose, therefore it can be used to sweeten your Saisons if you wish to do so.

Lactose is not fermentable by Saccharomyces brewers yeasts, there are some yeast strains that can work their magic on lactose or galactose.

Some strains of Brett can ferment out lactose others cannot. Here is a table from Gilliland 1961:

enter image description here


I cannot think of any strain of brewer's yeast that will take on lactose, but as mentioned different fermentations like sours and lambics can work with lactose and its derivatives. The fact that yeast can barely digest lactose is how people get milky flavors for things like cream stouts. The milk sugar just hangs around for flavor.

  • "The fact that yeast can barely digest lactose...". Non-GMO yeast does not express lactase and so cannot digest lactose in any way. Jun 5 '18 at 6:58

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