Multiple mashes -- possibly dumb question

[Mr_Beer]

Like most folks I have some space and equipment limitations.

Currently I can prepare about 10 gallons of mash in preparation for fermentation. Fermentation is then started on-grain in a fermentation vessel that has much room left.

Could I start another 10 gallon of mash and after cooling dump it into the original fermentation container with more yeast?

Seems possible but there is much I do not know so advice would be appreciated.

[Dougmatt]

Yes. Read this for a better idea: viewtopic.php?t=65703

[Twisted Brick]

Could I start another 10 gallon of mash and after cooling dump it into the original fermentation container with more yeast?

Not a dumb question Mr_Beer although adding an additional amount of fresh wash (or wort) later to an active ferment is different than large batch mashing where yeast is simply pitched into the cooled final volume.

Over the course of a ferment, yeast undergo a series of phases that after a lag, transition from aerobic growth to anaerobic production of alcohol. You can add additional wash to your active ferment but it is best to do so while the yeast is still in the growth phase. The yeast will be hungry to consume more sugars so you will not have to add additional yeast. If the yeast population is nearing its peak (ideal) you may not see a lag in fermentation. The limiting factor will be the amount of oxygen available and may require a bit of oxygenation. Try to add a fresh wash that is as close to your active ferment's temperature as possible to avoid stressing your yeast.

[PLAYMP]

I also am wondering in a similar vein....would it be possible to acidify a mash temporarily to increase the shelf life while further batches are produced?

And then raise it back up with calcium hydroxide or something to a proper ph when ready to pitch yeast?

[Mr_Beer]

Thank you "Twisted Brick" for your insightful response. Once again, you have provided a reminder of the obvious -- the yeast are somewhat fragile and your treatment will affect the outcome.

You reminded me of the oxygen requirement and I would have forgotten -- but that is what aquarium pumps and filter stones are good for. Filter the input air and drop the stone in the wash for a couple of hours and the rest seems to take care of itself.

More importantly you did provide a time frame for addition -- during the initial yeast growth/lag stage. With the protocol I use (Go-Ferm and vitamins at pitch time) the lag time is most often less than two hours. After 24 hours I add about 50% nutrient in my two nutrient addition protocol. The remainder of the nutrient is added at day two or day three.

It seems that adding another equivalent amount of wash to an already fermenting vessel would overpower the combined results and set back fermentation. And that would then cause the nutrient addition time frame to be called into question. Experimentation could answer some of the questions but it seems that I should consider a Plan B instead.

Thank you for taking the time to respond.

[still_stirrin]

… but that is what aquarium pumps and filter stones are good for. Filter the input air and drop the stone in the wash for a couple of hours and the rest seems to take care of itself…

No. You do not want to add oxygen to a ferment once latent fermentation has begun. Latent fermentation is anaerobic (without oxygen) and adding oxygen will “oxidize” the ferment, creating off flavors that will spoil your product.

… during the initial yeast growth/lag stage. With the protocol I use (Go-Ferm and vitamins at pitch time) the lag time is most often less than two hours. After 24 hours I add about 50% nutrient in my two nutrient addition protocol. The remainder of the nutrient is added at day two or day three…

Adding additional nutrients after the initial ferment has progressed to the “latent” stage, likely is unnecessary. The yeast cells themselves provide nutrients for reproducing yeast (new cells). Additional nutrients won’t hurt, but really aren’t needed. They are valuable to add to the wort when you first pitch the yeast, but once the ferment has reached “high Krausen”, the cell population is adequate to begin latent fermentation.

… It seems that adding another equivalent amount of wash to an already fermenting vessel would overpower the combined results and set back fermentation. And that would then cause the nutrient addition time frame to be called into question…

Adding wort to a ferment will increase the volume in the fermenter and the yeast population (billions of cells per mililiter) will be reduced temporarily. However, active healthy yeast will naturally reproduce (called “budding”) to once again get to the required population for active fermentation. The airlock activity may slow or stop for a few hours, but it will quickly restart.

However, you do not need to stir or add oxygen to the “fed” ferment. The yeast will aggressively reproduce naturally.

… Experimentation could answer some of the questions but it seems that I should consider a Plan B instead.

Experimentation is a “tool” for learning, of course. But “experience” is the best educator. Have fun with it.
ss

[Twisted Brick]

Great information from ss. Yes, introducing oxygen into an anaerobic wort can oxidize your wort. Oxygenate the supplemental wort (stir it up a bit) prior to adding it to your ferment while its still in the growth stage. Yeast don't discriminate what they feed on and will start working on it right away.

Your growth stage is gonna last longer than 2hrs. During lag, yeast are busy multiplying over the course of 8 - 24hours. Exponential growth can continue for 1 to 4 days (a larger ferment will take longer). Depending on your initial pitch rate (starter vs no starter) you should have a 2 day (maybe 3) window to safely add your second volume of wash. In addition to batch size, the lower the ferment temp the longer it will take to conduct its business.

And like ss says, everything we do is a test for learning. I predict your amended ferment will finish dry just fine.

[Mr_Beer]

WOW!!

Thanks to "still_stifrin" and "Twisted Brick".

To help readers of this thread, my background included evaluation and development of software for mead versus yeast. Mead, depending on the honey used, is substantially deficient with some components/additives that yeast like. With that as a background, my pitch and nutrient addition is based on the fact that adding additional stuff is often not determinable. Consider humans -- too many vitamins for you personally are expelled as waste product. The same notion applies to yeast with the exception of nutrients that are added during the lag stage and early fermentation. You may overpower them and stunt yeast development.

"Twisted Brick" notion that there is a two to three day window for additional mash additions is comforting.

My conclusion is that adding mash addition to the fermentation vessel within 24 hours is acceptable and probably does not need additional yeast addition.

That said, my notion is to help folks (our yeast friends) along and add nutrients in day two and probably day four of the fermentation.

[shadylane]

my notion is to help folks (our yeast friends) along and add nutrients in day two and probably day four of the fermentation.

In my shed.
By day 2, the cap will have fallen.
By day 4, the yeast will be settling to the bottom.

If I was going to add anything to the fermenter it would need to be no later than day 1.

[Twisted Brick]

In my shed.
By day 2, the cap will have fallen.
By day 4, the yeast will be settling to the bottom.

If I was going to add anything to the fermenter it would need to be no later than day 1.

Interesting timeline, Shady. In all my years I have never had a (13gal) ferment take less than a week to finish. More like 10-12days. (It could be my water) Granted, I prefer to under-pitch and ferment (S-04 and US-05) at cooler ale temps, but possibly your ferments are smaller? Also, are you pitching a lb of yeast (bakers) dry directly into your ferment?

[shadylane]

Interesting timeline, Shady. In all my years I have never had a (13gal) ferment take less than a week to finish. More like 10-12days. (It could be my water) Granted, I prefer to under-pitch and ferment (S-04 and US-05) at cooler ale temps, but possibly your ferments are smaller? Also, are you pitching a lb of yeast (bakers) dry directly into your ferment?

16 gallon fermented with bakers @ 86f
4ish grams per gallon of yeast.

[Twisted Brick]

That pitch rate is a bit on the higher end, Shady. No wonder your ferments finish so fast!

[shadylane]

That's why it's difficult to judge how far along a ferment is based on days.
There's too many variables, because folks do things different.

[shadylane]

Also, are you pitching a lb of yeast (bakers) dry directly into your ferment?

It takes awhile for me to use a pound of yeast anymore.

I use a drill to whip the mash into a vortex.
Wait till the liquid is slowly rotating and evenly sprinkle bakers on the surface.
I don't stir the yeast into the mash. The yeast sits on top and multiplies.
After a while it seems the yeast falls and fermentation starts big time.

That's only one of many ways to getter done.
Anyways didn't mean to hijack some ones post.

[Twisted Brick]

It takes awhile for me to use a pound of yeast anymore.

I use a drill to whip the mash into a vortex.
Wait till the liquid is slowly rotating and evenly sprinkle bakers on the surface.
I don't stir the yeast into the mash. The yeast sits on top and multiplies.
After a while it seems the yeast falls and fermentation starts big time.

That's only one of many ways to getter done.
Anyways didn't mean to hijack some ones post.

I'm a big fan of the mixer paddle too. I love the way it makes a convenient 'funnel' to pour my starter into as it aerates the wash.

Based on the regular emails I've been trading with Mr_Beer over the last 3mo's I can safely say he's not feeling any perceived hijacking. He is a master brewer and keen to pick up distilling principles, much of what he's read on his own. I'm sure he's happy to vacuum up any tidbits of info he reads on his threads and stores them in his quiver.

[Saltbush Bill]

Could I start another 10 gallon of mash and after cooling dump it into the original fermentation container with more yeast?

I did a similar thing very recently when fermenting enough to make a start on filling a 20 L barrel with a Scotch style Whisky.
You should not need to add more yeast after the first lot IMO.

Below is what I wrote on another forum at the time , as you will see I used very little yeast and it was enough to eventually ferment about 190 liters.
I've cut n pasted to save on typing.
The short clip was taken about 4 hours after the very last mash was added.
I was worried in the beginning about infection setting in before I had finished the last mash. That didn't happen until about 3 days after fermentation was complete ...so all was well.

" The first day I mashed enough grain to half fill a 28L fermenter. Added one small pack (11.5grams) of US-05 to that .
The next day I had time for a bigger mash , this was enough to filled another 28 L fermenter plus top up the first one, I transferred 5L from fermenter 1 into fermenter 2........both where fizzing away quite happily within a short time.
A few days later I made a bigger mash and tipped the contents into my large stainless 200L fermenting tank......let it cool then emptied both No 1 and No 2 fermenters into it.
When ever Ive had time I mashed yet more, let cool and added that ......the last one mashed was last night....I tipped the results in this morning once it had cooled.
At this stage the tank has approximately190L in it, there is no sign of any sort of infection, and everything is fizzing along nicely.
There was a break of a few days before I tipped this latest lot in and before I did the ferment was slowing and was almost done I think.....it picked up very quickly once I added the new lot."

[Twisted Brick]

When ever Ive had time I mashed yet more, let cool and added that ......the last one mash was added last night....I tipped the results in this morning once it had cooled.
At this stage the tank has approximately190L in it, there is no sign of any sort of infection, and everything is fizzing along nicely.
There was a break of a few days before I tipped this latest lot in and before I did the ferment was slowing and was almost done I think.....it picked up very quickly once I added the new lot."

You know Bill, what you essentially did was build a starter that you then stepped up three times, with increasingly larger washes. Conventional wisdom has it to add your additional wash just as the original starter reaches its peak cell count, making it easy for the yeast to 'assimilate' the next batch of fresh wash. What a great way to build a larger-volume ferment while maximizing yeast performance.

[Saltbush Bill]

It was all experimental at the time Twisted....gut feeling was that it would work.
You could look at it that way, building a large starter...or maybe even step feeding....whatever, it worked fine , save me a heap on yeast....those tiny lil packs of US-05 ain't cheap.
I wouldn't hesitate to use the same method again.
In theory, if you had enough fermenter, and big enough , you could run continuously that way on a commercial scale......but I'm sure they already do that anyway.

[shadylane]

Sounds like a good way to getter done Salty.

Another option is to scoop a bucket full off the top of an active ferment.
And pitch in the new batch.