Could you explain your sour mash method?

[Silk City Distillers]

Thanks for the insight on backset ratios - it’s an interesting topic.  How far can you reasonably push?  Where is it beneficial?  At what point does it become detrimental?

Not asking you to answer that, but interesting to read 20-25%, that’s the ballpark number that many of us think is the high-end.

 

[Southernhighlander]

27 minutes ago, Bill Fender said:

I worked at Brown-Forman Distillery 19 years, plant engineering manager.  I think you confused mash with backset.  Backset is screened to remove solids in all of the operations I'm aware of.  As I mentioned, most all big operations use centrifuges for very high suspended solids removal, of backset.  Suspended solids removal also enhances evaporator performance.     

Okay I gotcha.  I didn't realize you were referencing backset.  You said the stillage was screened.  Generally stillage means spent mash but I've seen some that use it to mean mash in general.  Not knowing your background I thought that you meant the latter.  Now that I understand, you gave a nice explanation.  

[Bill Fender]

3 minutes ago, Silk City Distillers said:

Thanks for the insight on backset ratios - it’s an interesting topic.  How far can you reasonably push?  Where is it beneficial?  At what point does it become detrimental?

Not asking you to answer that, but interesting to read 20-25%, that’s the ballpark number that many of us think is the high-end.

 

The QC Specialist at the distillery did a study at University of Louisville (think it was UofL) and that's what he told me.  Yes, that would be high end.  He told me going that high would be highly dependent on keeping backset sterile and most likely per cent solids in the backset.  That distillery uses a screen, not centrifuge.  I know fuel alcohol use a much higher percentage.   

[Bill Fender]

23 minutes ago, Silk City Distillers said:

Thanks for the insight on backset ratios - it’s an interesting topic.  How far can you reasonably push?  Where is it beneficial?  At what point does it become detrimental?

Not asking you to answer that, but interesting to read 20-25%, that’s the ballpark number that many of us think is the high-end.

 

Sorry I'm working as well as following along.  My pal told me 25% was tops.  That's all I know.  He was helping me as a small distiller was looking to reduce slop hauling and using setback is a big help.  I also know fuel alcohol plants run much higher off the centrifuges.  Benefits?  Reuse of water, reducing waste water is a benefit.  Reducing slop hauling, always a PIA!  As mentioned by others, my plant manager told me yeast prefers a lower pH.  As far as detrimental I was told a solids buildup was the biggest obstacle.  That's why centrifuge plants can run so much higher.  As I mentioned in my intro, I'm not a distiller, just worked for one nearly 20 years.  Mostly know from osmotic pressure!  If you would like to contact my pal send me an email, bill@wmfenderassociates.com.  He says he wants to consult so he can use the practice.  Please use my name.  Hopefully this is helpful.     

[AK2]

I was a lab manager and a production manager for an ethanol fuel plant for 7 years.  We used 30% to 40% backset depending upon plant conditions, centrifuges took almost all solids out (backset that was not used was sent to evaporators and turned into syrup that was sprayed on the DDGS).  pH was too low for enzymes to work properly with that much backset added, so we used anhydrous ammonia to the slurry tank, pH was set for 5.8.  We then added sulfuric acid post liquefaction tanks to get pH to a 5.2.  In our plant if we let the pH get above 5.4 the infection would take over, no matter how "clean" the plate and frame heat exchangers were.  Never could find the dead leg where the bacteria was hiding, just made sure to have plenty of sulfuric on hand to keep everything running smooth.  I do not have much to add on the sour mash portion, but I saw fuel ethanol mentioned and for ONCE I could speak intelligently on this board!  

Adam 

[Bill Fender]

3 minutes ago, AK2 said:

I was a lab manager and a production manager for an ethanol fuel plant for 7 years.  We used 30% to 40% backset depending upon plant conditions, centrifuges took almost all solids out (backset that was not used was sent to evaporators and turned into syrup that was sprayed on the DDGS).  pH was too low for enzymes to work properly with that much backset added, so we used anhydrous ammonia to the slurry tank, pH was set for 5.8.  We then added sulfuric acid post liquefaction tanks to get pH to a 5.2.  In our plant if we let the pH get above 5.4 the infection would take over, no matter how "clean" the plate and frame heat exchangers were.  Never could find the dead leg where the bacteria was hiding, just made sure to have plenty of sulfuric on hand to keep everything running smooth.  I do not have much to add on the sour mash portion, but I saw fuel ethanol mentioned and for ONCE I could speak intelligently on this board!  

Adam 

Adam, your intelligence quotient on the chemistry is way over my pay grade!  I knew ethanol production had a high backset percentage.  I know you aren't looking for the bugs any more but a war story from my past.  We had 6" diaphragm fermenter drop valves.  In order to automate the valving we changed to butterfly valves.  Problems with fermenters going sour had the boss looking for the problem.  Long story short, there was an area above the butterfly valve holding 2-3 gallons of condensate that did not heat up enough to kill the bugs.  I think we installed an automatic valve to drain this void, eliminating the contaminated water.  Hot condensate kept the void sterile very nicely.  I remember the mash line was always hot.  As I recall, as soon as the mash pump shut off, the mash line steam valve and drain valve, opened.    

[Silk City Distillers]

Good stuff!  Keep sharing.