Very interesting papers on biosorption of heavy metals by brewer's yeast

[blacksquid]

Hopefully these haven't been posted before, used google search.

So, being quite broke after spending a lot of money on a pump (local deal I couldn't pass up on!), plate chiller and SS fittings, I was wondering if I could cut some corners and use more brass fittings (I already use them on my MLT)... I was quite set about making the move to go all SS for fear of lead leaching.

On an old thread somebody talked about "yeast eating lead" and made me curious. So I found these old and recent studies that did put my mind at ease (somewhat!):

http://repositorium.sdum.uminho.pt/bitstream/1822/1371/1/1999-10%255B1%255D.pdf

http://etd.aau.edu.et/dspace/bitstream/123456789/2679/1/29986188681294640775326040088047563662

http://www.aseanfood.info/Articles/11016996.pdf

 

[BBL_Brewer]

I don't think those findings correlate well to brewing as the yeast is dead, dried and ground before applied. It doesn't show that live yeast bind with heavy metals, which is the point of interest.

 

[blacksquid]

I'm far from saying it'll definitely correlate in our uses but those are interesting findings nonetheless. There will also be dead yeast in a fermenter.

I'll need to read all of those in-depth.


Also, it is true of the Chinese and Mesfin study but:

Excerpt from Feiraz, Teixera study:

"2.1
Microorganism
S. cerevisiae was obtained from UNICER, a Portuguese
brewing industry, at the end of fermentation when it
presents the highest flocculating capacity (Teixeira et al.,
1991). Biomass suspension was prepared by washing 50 g
of wet yeast in distilled water, followed by centrifugation
(3 minutes, 3000 rpm). This procedure was repeated three
times. Washed biomass was finally suspended in 100 ml of
distilled water. This final biomass suspension was added to
metal solutions in quantities depending on biomass con-
centration, referred as biomass dry weight/l, required in
each essay"

 

[Nablis]

Colin kaminski talked about how the state of California wanted to test his beer because he had a copper kettle, they wanted to make him go to stainless. They tested the beer before fermentation and there was copper in it. They tested the finished product and there was no copper in it.
Sorry no papers to show you facts.
Yeast has a proclivity to metals and pulls metals out of solution.