Author: Steve Thanos
Nearly every style of beer is known for possessing some level of bitterness to balance out malt sweetness, and this primarily comes from the isomerization of alpha acids that occurs when hops are added to the boiling wort. Once the boil is complete, brewers aim to transfer clean wort to the fermenter, hence many rely on some form of hop filtration, a common option being fabric bags.
A popular material used for hop filter bags is muslin, a lightweight and flexible cotton fabric with a relatively loose weave that allows wort to easily flow through. Given its absorbent quality, some believe using muslin hop bags can reduce overall hop character in beer, which is of particular concern when making IPA. For this reason, many brewers opt for bags made of polyester, which in addition to being more durable and less stretchy than muslin, is almost completely non-absorbent.
I’ve used both muslin and polyester bags extensively in my brewing, usually going with whatever is most readily available when my wort reaches a boil. While I can’t say I’ve noticed either as being better or worse than the other, I was curious if the different materials might have a perceptible impact on a hoppy IPA and designed an xBmt to test it out.
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