Trub Processing and Disposal

Question 1

What is trub?

Answer 1

A significant amount of extract that remains after wort separation, often containing 80-90% wort.

Trub is primarily composed of proteins, hop residues, and other particulates from the brewing process.

Question 2

What are the two ways to recover extract from trub?

Answer 2

• Add the trub back to the mash vessel or lauter tun before wort separation
• Process the trub further to recover the extract

Question 3

What is a common practice for adding trub to a subsequent brew?

Answer 3

Store in an insulated tank before pumping on top of the grain bed before lautering.

This practice is not common due to potential quality issues.

Question 4

What are the potential negative components found in trub?

Answer 4

• Lipids
• Polyphenols

Question 5

What equipment can be used to process trub further?

Answer 5

• Decanter centrifuges
• Vibrating screen filter/separator

Question 6

How does a decanter centrifuge work?

Answer 6

It processes trub by settling it to the bottom of the wort clarification vessel and recovering wort combined with the wort cast out to the fermentation vessel.

Question 7

What is the function of a vibrating screen filter/separator?

Answer 7

It shakes the trub vigorously, allowing wort to fall through the screen while trub moves across to the outlet for disposal.

Question 8

What is the typical quality of wort recovered using a vibrating screen filter/separator?

Answer 8

Usually very turbid, but the volume returned to the brew is small.

Question 9

What is a hot trub tank used for?

Answer 9

It allows trub more time to sediment while clarified wort is drawn off and combined with a subsequent brew.

Question 10

What precautions must be taken when recovering wort from trub?

Answer 10

Care must be taken due to the presence of undesirable components, and its effect on beer quality must be monitored continually.

Question 11

How is trub typically disposed of?

Answer 11

• Added to spent grains inside a lauter tun before discharge
• Added to spent grains hopper below the lauter tun or mash filter for discharge

Question 12

What can be done with combined trub and spent grains?

Answer 12

• Sent to an anaerobic digester
• Sold for cattle feed
• Sold as a co-product

Question 13

What can be done with spent whole hops?

Answer 13

• Combined with spent grains for sale as feed
• Composted
• Spread on land