McMullan
wort maker
- Joined
- Dec 22, 2015
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The shape isn’t that important. You see Yorkshire rounds in some modern traditional breweries. And mines round rather than square too. I suspect it was just easier to make square Yorkshire squares, especially in stone, at some point in history, to occupy square brewery buildings. Equally, there’s no reason why we can’t use a single round FV as a standard square. Especially at home-brew scale.
The more vigorous rousing achieved using a Yorkshire square/round is more to do with breaking up the considerable volume of flocculant yeast on the bottom of the yeast trough (around the man or yeast hole, which projects up a little from the base) and washing it back into the FV below. The spraying wort merely channels a cavity through a small area of the yeast head foaming on top. Not all standard squares have ‘fishtails’ for spraying wort either. Some won’t recirculate wort at all. It depends on the yeast strain. Some top-cropping English strains don’t respond well, with the yeast head collapsing when sprayed. Ideally, it should grow and stabilise when sprayed. That’s what true Yorkshire strains do. Not sure why, but I suspect it has something to do with how the yeast cell wall interacts with evolving CO2, clinging on to it long enough to hitch a ride out of the wort and escaping into the yeast trough.
The more vigorous rousing achieved using a Yorkshire square/round is more to do with breaking up the considerable volume of flocculant yeast on the bottom of the yeast trough (around the man or yeast hole, which projects up a little from the base) and washing it back into the FV below. The spraying wort merely channels a cavity through a small area of the yeast head foaming on top. Not all standard squares have ‘fishtails’ for spraying wort either. Some won’t recirculate wort at all. It depends on the yeast strain. Some top-cropping English strains don’t respond well, with the yeast head collapsing when sprayed. Ideally, it should grow and stabilise when sprayed. That’s what true Yorkshire strains do. Not sure why, but I suspect it has something to do with how the yeast cell wall interacts with evolving CO2, clinging on to it long enough to hitch a ride out of the wort and escaping into the yeast trough.