I am just an extract brewer; I buy everything from NB. The instructions say:

"Fill primary fermenter with 2 gallons of cold water, then pour in the cooled wort. Leave any thick sludge in the bottom of the kettle."

I typically follow this instruction, but it seems odd to me. I can see from the colorization that there are traces of hops in there.

1) What is the point of this?

2) Should I continue to do it?

2 Answers 2


The sludge is mostly coagulated proteins, hop residue. A little bit is actually good for your wort, as it provides nutrients for the yeast. Too much might give the beer some slight off flavours. If you were to let the sludge into the fermenter, it wouldn't be the end of the world, but you'll make better beer if your exclude most of it.

So, to answer your two questions:

1) The point is to reduce off flavours in the finished beer.

2) Yes, continue to do it but don't be too worried if some of the sludge makes it into the fermenter.


In general the kettle sludge from an extract batch isn't going to hurt things any. As long as you perform a strong healthy fermentation the beer will be ready for transfer faster than that sludge will significantly effect the beer.

The hop part of sludge may contribute some more hop resin depending on when it was added to the boil originally. The larger fear being some vegetal character coming from it if the beer is left in primary for to long.

However, the less stuff in your fermentor the less time it will take for your beer to clear downstream of the fermentation.

So its a balancing act and one that gets debated often. I don't think there is a real answer here. Do the best you can, be consistent with your process, experiment batch to batch and figure out what works for you.

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