87 replies to this topic

[codemonkey]

Yep.  I can't think of any way conversion could be taking place during fermentation.

You surely know a lot more about this than I do, but there are a number of articles both in print and online that are similar to this:

 

 

Alpha amylase converts starches into about 80% maltose and 20% dextrins.  After the cooking process distillers yeast is introduced into the mash and converts sugars into alcohol which reduces the sugar content.  At a certain point in the fermentation process the beta amylase enzyme, which is still active in the mash, initiates a secondary conversion of starches into sugars which increases the alcohol yield.

 

 

source

[denny]

those have been shown to be of limited benefit but maybe for a really high gravity situation it could help I guess.

 

oh you mean like this? 

 

It's early here...what can I say? 

You surely know a lot more about this than I do, but there are a number of articles both in print and online that are similar to this:

 

 

source

 

Sounds like you know more than I do!

[positiveContact]

It's early here...what can I say? 

 

Sounds like you know more than I do!

 

the key is he never denatures those enzymes.

[denny]

the key is he never denatures those enzymes.

 

But time and pH will denature them.  I would have guessed that happened before the ferment.  Guess not.

[positiveContact]

But time and pH will denature them.  I would have guessed that happened before the ferment.  Guess not.

 

I knew time would.  what pH will do it?

[neddles]

But time and pH will denature them.  I would have guessed that happened before the ferment.  Guess not.

Yeah I would have thought the pH drop of fermentation would stop the conversion/enzyme activity if they were still present too.

[positiveContact]

Yeah I would have thought the pH drop of fermentation would stop the conversion/enzyme activity if they were still present too.

 

what pH starts to become problematic?

[neddles]

what pH starts to become problematic?

I can't remember. Ill do a little digging when I have some time.

[positiveContact]

I can't remember. Ill do a little digging when I have some time.

 

I would guess due to lag time it would be at least a couple of days after the mash before pH starts to have an effect.  I'm betting time matters first.

 

so since there is no boil how does one rely on everything that was in the water being "dead" when mashing and then immediately fermenting?

[neddles]

I would guess due to lag time it would be at least a couple of days after the mash before pH starts to have an effect.  I'm betting time matters first.

You are probably right.

 

so since there is no boil how does one rely on everything that was in the water being "dead" when mashing and then immediately fermenting?

 

I wondered that too.

[codemonkey]

so since there is no boil how does one rely on everything that was in the water being "dead" when mashing and then immediately fermenting?

Are you referring to wild yeast and/or bacteria?

 

Whisky fermentation is quite similar to beer fermentation, but there are couple of important differences; the wort is not boiled, the distiller's yeast is usually propagated aerobically and the fermentations are usually not aeriated or temperature controlled (except the starting temperature). Unboiled wort allows the enzymes to continue their work and break down the oligosaccharides to increase the alcohol yield, but it also enables contamination with bacteriae and wild yeasts. If the yeast used is propagated aerobically, it is faster to start the fermentation and contains more sterols and fatty acids and thus the wort needs less oxidation or rousing.

source

 

My take on this at hobby scale is to just overpitch so the exponential phase is as short as possible. 

Edited by codemonkey, 27 October 2014 - 10:34 AM.

[denny]

I knew time would.  what pH will do it?

 

enzymes only work in certain pH ranges.  As the beer ferments, the pH drops.  I don't really know when it would happen, but here's the chart from How to Brew...

 

I would guess due to lag time it would be at least a couple of days after the mash before pH starts to have an effect.  I'm betting time matters first.

 

so since there is no boil how does one rely on everything that was in the water being "dead" when mashing and then immediately fermenting?

 

Actually, IIRC it's just a few hours.  It would be interesting to check gravity over the course of the first few hours in the fermenter.  If conversion is still taking place, seems like it would continually go up.

[positiveContact]

Are you referring to wild yeast and/or bacteria?

 

source

 

My take on this at hobby scale is to just overpitch so the exponential phase is as short as possible. 

 

so you are mostly relying on the yeast you pitch to take over quickly.  i'm surprised you don't care about the fermentation temps.  wouldn't higher order alcohols be bad for the final product?

[codemonkey]

so you are mostly relying on the yeast you pitch to take over quickly.  i'm surprised you don't care about the fermentation temps.  wouldn't higher order alcohols be bad for the final product?

Yes, but shit gets complicated real quick. If its boiling point is close to that of ethanol it's problematic. I struggle with diacetyl. Ferment too long and autolysis releases some untasty stuff. Too quick and you've got butter. I tend to be on the buttery side, and I'm starting to wonder myth vs science regarding autolysis.

Edited by codemonkey, 27 October 2014 - 10:55 AM.

[SchwanzBrewer]

Is there a good reason not to make a clean beer prior to distilling?

[codemonkey]

Is there a good reason not to make a clean beer prior to distilling?

Time and fuel come to mind. I guess the reverse question is more important - is there any benefit to clean beer prior to distillation?

[SchwanzBrewer]

Time and fuel come to mind. I guess the reverse question is more important - is there any benefit to clean beer prior to distillation?

 

My guess would be, and this is most certainly a WAG, that a clean fermentation with little left over acetaldehyde or diacetyl would make for a finer distilled product. It might make your efficiency go down, but the overall quality goes up. Is it worth a few extra % ethanol if you have to distill your (forgive me I can't remember the terms) first runnings and tailings again to get more out of the process? Also is it worth having off flavors as a result of a slightly off fermentation?

 

If you could make a 10% clean beer with higher relative efficiency on the distillation (fewer first runnings and tailings to throw out or redistill), wouldn't that make for an overall better end product?

[codemonkey]

I don't think it makes enough of a difference in the final product to justify the effort. Some of the off flavors in the wash don't come through, and some of them react with the copper to produce desirable flavors. It's possible to be too "clean" when it comes to whiskey and end up with something that doesn't really have a lot of flavor.

[SchwanzBrewer]

I don't think it makes enough of a difference in the final product to justify the effort. Some of the off flavors in the wash don't come through, and some of them react with the copper to produce desirable flavors. It's possible to be too "clean" when it comes to whiskey and end up with something that doesn't really have a lot of flavor.

 

So basically, way too complicated. I get it. 

[positiveContact]

So basically, way too complicated. I get it. 

 

yeah - it sounds like all of the best practices that we would use as brewers really might not apply here!