Constant sugar concentration?

[pHneutral]

I've looked about.. but couldn't find out if anyone had posted on this before.

I have seen many talk about adding sugar in stages to washes, but I was curious if there is a thread that talks about keeping the sugar concentration relatively constant throughout the entire ferment? Any kind is fine.. juices, sugar water, molasses water, etc. I'd just like to see if this has been covered here or not.

I'll keep looking, but thanks in advance!

[punkin]

Don't think so (and i've read everything here at one time or another).

Are you talking about setting up some kind of measured drip feed system?


Do you feel it may be better than fermenting in batches?

[rad14701]

There have been minor discussions about the incremental addition of sugar... Problem is sugar doesn't kill yeast, ethanol does... The fact that folks have been able to ferment sugars into ethanol in as little as 24 - 36 hours makes incremental addition not worthwhile... Not to mention that adding sugar to a fermenting wash will cause it to foam up... Personally, I'm not sold on the concept...

[minime]

There have been minor discussions about the incremental addition of sugar... Problem is sugar doesn't kill yeast, ethanol does... The fact that folks have been able to ferment sugars into ethanol in as little as 24 - 36 hours makes incremental addition not worthwhile... Not to mention that adding sugar to a fermenting wash will cause it to foam up... Personally, I'm not sold on the concept...

I agree with Rad 100%. Stepped addition and inverting are a waste of time IMO. Plus you could end up with a large volume of your wash on the floor is you don't de-gass it well enough.

[Tater]

I would agree on the step adding but not with the inverting.Not that it ferments any better /worse but in taste it has in product.

[junkyard dawg]

Inverting sugar makes a huge difference in flavor for wines and distillates. At least in my experience...

I could care less about stepped sugar addition. For drinking, 10% washes are just fine... no need to make it any harder for no reason.

[HookLine]

Problem is sugar doesn't kill yeast, ethanol does...

High sugar concentrations (ie high osmotic pressure) can certainly make life a lot harder for yeast, which can produce more off flavours and make them work slower.

Having said that, I agree that stepped addition is probably mainly useful for high % abv ferments (ie for the fuel guys), to reduce the osmotic pressure on the yeast at any one time. If, like us beverage distillers, you are not going above 10% then it is probably not a major advantage. (Although if you are shooting for maximum quality, then stepped addition is not going to hurt, and controlling the excess foaming from the de-gassing is very easy, just add the additional sugar solution s-l-o-w-l-y over 2-3 minutes.)

Can't comment on inverting, haven't tried it enough to know.

The Chemist might be able to enlighten us further. (Hint, hint. )

[pHneutral]

Thanks very much. The thought came to me when I read over Sake making, as that is what is essentially happening there. I figured that it had at least been talked about a bit here.

I was just curious if it might change the flavor profile and up the final ABV a bit. No one's tried it out on a flavored spirit?

FYI I was actually talking about adding it at a much slower rate, in order to keep the sugar % constant throughout the ferment. I was just curious

Don't worry! I'll be doing my first dozen or more washes the reg'lr way

[rad14701]

I'd be interested in knowing whether simply dumping more granular sugar into the wash is beneficial only in that it wouldn't dissolve as fast... Considering how most of us dissolve our sugar in hot or even boiling water it seems that there would be a difference, especially osmotic pressure as HookLine mentioned... Of course you would still need to consider the overall fermentation time when considering stepped additions... It might be beneficial for a longer fermentation period but not for a low ABV wash...

[punkin]

Thanks very much. The thought came to me when I read over Sake making, as that is what is essentially happening there. I figured that it had at least been talked about a bit here.

I was just curious if it might change the flavor profile and up the final ABV a bit. No one's tried it out on a flavored spirit?

FYI I was actually talking about adding it at a much slower rate, in order to keep the sugar % constant throughout the ferment. I was just curious

Don't worry! I'll be doing my first dozen or more washes the reg'lr way

Sorry, that's what i thought you talking about. a gradual, continual addition rather than a stepped process (which there is plenty of discussion hereabouts).

I still don't think i've seen anything on a gradual addition process and still don't see what the benfits it'll bring that outweigh the complications. If ya have a theory i'd be interested to hear it.

[pHneutral]

Thanks guys, for entertaining a greenhorn's notions

Well, I was just thinking that if you had a colony at its happiest sugar percentage the entire ferment (around 2%), they might be healthier overall, and more capable of dealing with various other conditions, like the alcohol percentage rising. It also means they would be less stressed and you would get a different tasting product from a regular run, which may be good or bad depending on what you want. Also, you wouldn't have much die off near the beginning, and thus you'd have a larger population of cells, so you'd have more genetic diversity, and a better chance of developing heartier progeny.

As far as addition goes, of course.. you wouldn't want to add the sugar dry. You could work it out with a warm solution of saturated sugar + nutrients (except for any solids. I'd guess you could just pitch in a bit of yeast hulls from time to time) in a vessel that had a slow stirrer (just some cheap gear motor connected to an old kitchen aid beater), and a calculated drip rate based on how fast the yeast were working. Or you could just do it over a fixed time period, like 72 hours or so. Or if you wanted to ferment more slowly, use that time period instead. I'm guessing though that the sugars that were there would get fermented a bit more quickly, so you would have to play with addition rates. It might also make sense to sparge out your sugar solution for a few minutes with N2 to get rid of oxygen, but I dont imagine that would be necessary.

Another advantage is that you can control the sugar concentration at any moment, and thus control the fermentation rate and temperature, directly. You wouldn't have to worry about foaming over, or overheating. In fact, I would bet the temperature would remain relatively constant throughout the process. You could even do various things like forcing a bit of stress at points during the ferment, to see what effect it had on the final flavor and %ABV.

Since you're going through all this trouble, you could also stir your ferment slowly to keep it from stratifying. Unless thats what you want If you did stir your ferment, it would probably be good to be a slow, and non shearing mixer (like a few stacked discs with a few holes drilled in them near the spindle, or even easier.. just a length of stainless wire shaped like a tear drop near the end)

Its definitely a bit complicated, but it provides a whole new toy to play with. And since this whole thing is just one, big, giant toy for me to play with, I like that

Now, this could also mean that the fermentation might be more likely to stick.. I don't know. But if you were adding nutrients along with the sugars in good ratios, I would think that would prevent malnutrition. Or you could put ALL the nutrients in the fermentation tank, and only drip over the sugars.

Thats pretty much the whole spark. I dont think this setup is any more complicated (less even) than making up a VM reflux still, especially considering it doesn't involve winding copper, soldering and brazing!

[punkin]

I gotcha, so you could have a tap say half way or so down and draw off enough for a charge and wait for it to recharge that half volume to grab the next charge. All the while keeping less (but growing) volume at the same constant %.

One issue you'd have to deal with would be to stop infection or sponntaneous fermentation in your sugar holding drip vessel.

A magnetic stirrer would be adequate.

I don't know if the benefits would beat batch fermenting, but it's an interesting concept to explore.