In search of solutions to manage spent Yeast

Hi everyone
I'm writing from Sri Lanka. My interest is in developing a sustainable solution for handling waste at brewery with special focus on spent yeast. I am keen to investigate methods of biological flocculation so that excess beer (liquid) can be removed and yeast dried, mainly to be used in animal feed. I would appreciate if I can collaborate with others with similar interest

Fun point - Whilst almost all material on yeast talks about preventing clumping (flocculation) I am trying to accelerate the process / achieve sedimentation / separate solid from liquid.

Look forward to collaborating !!

Welcome, Sriyanthaw!

This forum is focused on home brewing of beer, but your quest isn't lost on us.

In the US, the Sierra Nevada Brewing Company is leading the small Craft Brewer's industry in it's sustainability efforts. New Belguim has also developed strong sustainability programs.

Heavier flocculation without adding finings is going to be conditioned by pH, temperature, and yeast genetics. A centrifuge is the fastest and least wasteful method of separation. It's good for the bottom line, too. It can create yields up to 96%.

There are numerous papers on ethanol separation, using yeast on spent grain to increase yield, plus other methods of yeast separation & reuse found in both the ASBC (American Society of Brewing Chemists) and the MBAA (Master Brewer's Association of America). I know there are similar groups in Europe and Asia. I believe articles are shared between the various associations.

One of the more common methods of using spent yeast for feed is centrifuging to 50% moisture, autolyzing the slurry at 60 to 65C, then mixing with reduced moisture spent grain and kilning the whole lot to dry. The autolyzed yeast is then safe for consumption by various animals that would get colic from living yeast. Another method calls for liquefying the grain with steam, then adding the autolyzed yeast and extruding the slurry under pressure to get "cooked" pellets, similar to making certain snacks and breakfast cereals.