Continuous fermentation

[Lassiter Distilling Co]

We've been experimenting with ways to ferment. Our standard SOP is the batch method, where we produce our wash (we make rum) let it ferment out and then empty/wash the fermenter once it's been transferred to the still. 

One day, we left some of the wash along with the trub in the bottom of the fermenter before refilling with new wash. The fermentation time was dramatically reduced, with only a 30 minute lag time and a total fermentation of only 33 perent of our typical time. I was primarily concerned with bacterial infection and stressed yeast affecting the flavor of the distilled product, but it came out perfectly. 

Has anyone seriously experimented with continuous fermentation? Anything to look out for/good or bad experiences? If this works we may adjust our SOPs as it will save on time and the amount of yeast we are using. 

[jeffw]

Never tried but I like the idea.  What percentage of the ferment did you leave in there?  Did you repitch yeast at all?

[Foreshot]

It's the way they did it in the old days. Watch for changes in the yeast over the generations, I read in "Yeast" that the yeast can get damaged and cause it to change flavors/attenuation/alcohol yield. If I remember correctly it was around 7 generations that he suggested going back to a more pure version. 

[3d0g]

Shouldn't need to repitch as this is in effect massively OVER pitching. Hence the short lag and fermentation. You lose the flavor compounds from yeast growth but that's probably not as big a deal for rum.

[Natrat]

Keep an eye on mutations. Another thing is to periodically acid wash your pitch. Biggest issues with continuous processes is crud buildup in your equipment. Have fun!

[Curators Reserve]

Some great reads on various other Distilling Forums on multiple generation washes & also Dunder/ Backset etc.

Have you done any cost benefit or pro's & cons on doing this.

You looking at a larger wash & removing a % for each stripping run - to then top up & continue the ferment?