Skip to main content

Don't be afraid of the Trub!

In a lot of home brewing books, and perhaps in the minds of many home brewers, is the advice that you should separate your beer from the trub during fermentation.  (Trub, also known as lees, refers to the sediment that appears at the bottom of the fermenter.) The prevailing wisdom is that trub will cause the finished beer to be more cloudy, have "off flavors", and generally turn out worse than a beer moved off the trub into a secondary fermenter.

The folks who make the Grainfather did an experiment in February to see if the prevailing wisdom is correct.  Would a beer kept on the trub throughout its fermentation taste worse, look more cloudy, have poorer head retention, etc., than a beer removed from the trub?

For the experiment, they brewed an American Pale Ale (APA).  Half of the batch was fermented with as little sediment as possible.  The other half was given as much sediment as possible.  If the trub made any difference in the beer, this experiment should make that difference very obvious.  Their recipe for the APA was:

  • 4.5 kg pale malt
  • 1 g Simcoe hops at 60 minutes
  • 150g of Simcoe hops at whirlpool
  • Mangrove Jacks Burton Union yeast

After brewing, half the batch was poured through a sanitized sieve to strain all possible particulate matter out of it.  The other half got all the trub when it went into the fermenter.

The beers fermented identically, starting with a gravity of 1.044 and ending with 1.005.

After 7 days, the fermenters were moved to a refrigerator to cold crash them before bottling.  After chilling, another gravity measurement was taken to ensure that gravity had remained the same.  It had.  A quick taste test showed that the sample from the trub-filled fermenter actually was more bitter than the one from the trub-free fermenter.

They got 14 bottles from the trub-filled fermenter and 18 from the trub-free one.  So if you want better yields, avoiding trub is a good idea.

A blind taste test was then performed of the two beers after bottle conditioning.  Tasters were asked to judge the clarity, aroma, head retention, and comment on any off flavors they detected.  The results were surprising.

The beer brewed with the trub was judged to be clearer by all four tasters.  It was also judged to have the better aroma.  Tasters were split 50/50 on head retention, but all agreed that it was similar for both beers.  But home brewers probably care most about flavor...  how did that turn out?

All four tasters preferred the beer fermented with the trub.  They said its flavors were clearer and more defined than the beer fermented without trub.

When asked to guess which beer had been fermented with trub, all four were wrong.

The conclusion arrived at by the brewer were that a high proportion of trub can be beneficial.  It can improve clarity, aroma, and flavor.  The downside to leaving the trub in is that it did reduce their yield by 22%.  Perhaps it would be good to reduce trub but not eliminate it when homebrewing.

Whether you choose to leave the trub in your beer during fermentation or not, the good news is that you shouldn't have to worry if you can't get it all removed.  Your beer may actually benefit from a little trub making it into the fermenter.


Popular posts from this blog

Things I've Learned Brewing with The Grainfather, Part 2

In the last post, I shared an overview of The Grainfather, recommended equipment to use with it, and an overview of the brewing process.  In this installment, I'm going to talk specifically about mashing and sparging. Having brewed over a dozen batches with it, I'm finally becoming very comfortable with the device, the mash process, and how to get what I want out of it. I don't consider myself a "master" of it yet, though.

For those who have never done all-grain brewing, I want to provide a quick overview of the mash process itself.

Mashing - With or Without The Grainfather
The goal of mashing is to turn the starches in the grain into sugars. More specifically, you want to turn the starches into a mix of fermentable and unfermentable sugars that provide the flavor profile associated with the beer you are brewing. A sweeter beer might warrant more unfermentable sugars. A more dry beer will demand few unfermentable sugars.

To a great extent, controlling the amount o…

Brewing with The Grainfather, Part 3 - Cleaning and Overall Thoughts

In Part 1 of this series, I introduced The Grainfather and discussed how to use it for mashing and sparging.  In Part 2, we talked about boiling and chilling the wort with The Grainfather and its included counterflow chiller.  In this final segment, we'll discuss cleanup and overall thoughts about the device and its usage.


Once you've pumped the wort from The Grainfather into your fermenter and pitched your yeast, you're well on your way to a delicious batch of homebrew.  Unfortunately, you've still got some cleanup work to do.

The cleanup process in my experience will take 20-30 minutes.  It involves the following tasks:

Removing and discarding the grain from The Grainfather's grain basketCleaning the grain basket, kettle, recirculation tube, and wort chillerCleaning all the other implements used in brewing (scale, scoops, mash paddle, etc.) At the end of the brewing process, there will be hops bags (if you used them), grain and other residue, and usually so…

Brewing with The Grainfather, Part 1 - Mashing and Sparging

(Important note:  This article series is based on the US version of the product.  Prices are expressed in US dollars, measurements of temperature and volume are in US units unless otherwise noted.)

iMake's The Grainfather is an all-in-one RIMS brewing system designed to be used indoors with household electric current.  It includes the kettle, grain basket, recirculation tube, pump, electronic temperature controller, instruction book, and counterflow chiller.  It does not include a mash paddle, fermenter, cleaning supplies, or pretty much anything else.  The price is around $800-900 depending on where you shop and the discounts offered.

The Grainfather handles mashing, boiling, recirculating, sparging (to a degree), and chilling of the wort.  You'll still need a fermentation vessel of some sort and some other supplies we'll discuss later.

Grainfather Assembly and Initial Cleaning

Assembly of The Grainfather in my experience was pretty easy overall.  There were a couple of s…