Ask Mr. Wizard

Hot-Side Aeration

TroubleShooting

Mark Kutil — Germantown, Tennessee asks,
Q

I have an electric Brew-In-A-Bag (eBIAB) system which is outfitted with a mesh basket to hold the grains for mashing. There is a center post in the basket with holes to recirculate the wort. These holes form a ring around the tube and there are several sets of these hole rings from the bottom to the top of the tube. My concern is when the basket is not full, the wort is sprayed out over the grain bed through the holes several inches above the surface. I have had several batches come out of primary fermentation with an awful smell and taste and had to dump the whole batch. Is my assumption that the wort is exposed to too much oxygen during the mash causing this off-flavor?

A
Identifying that one problem, the thing responsible for the majority of brewing issues, is the dream of every brewer who knows that their beer is just one step away from greatness. And,
Response by Ashton Lewis.