[hackrsackr]

You’re confusing amalase derived glucose (standard mash) with maltase derived glucose (special mash.)


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[hackrsackr]

The yeast is what is irrelevant.


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[Robert]

Glucose is glucose.  What matters is how much of it there is for the yeast to do with as it will, no?

[hackrsackr]

During the standard mash amalase has not yet broken amylopectin down into maltose, while you are in the range that maltase is active. Maltase can not break down amylopectin branches. Maltase is then denatured before amalase make the 10% glucose.


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[hackrsackr]

The 114 rest will only make glucose/isoA if it has been broken down by amalase first.


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[The Beerery]

Everything we do on our scale is better than the best shallowest commercial fermenter there is.  Hydrostatically speaking that is.  A 5 gallon fermenter has very little.  I can’t imagine there is a difference. 


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[JJeffers09]

I thought the same.  Not to be an as what, but this isn't traditional, and tbh neither is my recipe at 60/20/20 dark wheat/munich/pils but it works

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[hackrsackr]

To clarify I think the pressure in the krausening or second ferment drives 4vg.

The isoA I believe is influenced by the access to oxygen through the growth phase. ie open ferm.


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[Big Monk]

To clarify I think the pressure in the krausening or second ferment drives 4vg.

The isoA I believe is influenced by the access to oxygen through the growth phase. ie open ferm.


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I would think the opposite is true, i.e. ester synthesis is stunted with larger amounts of yeast growth (access to oxygen). The open fermentation matters very little in our setting as any homebrew fermenter will promote higher levels of esters by default due to the geometry and scale. It’s why homebrewers tend to get better results with Trappist yeasts by limiting fermentation temperature even though it often differs greatly from the commercial examples.

[The Beerery]

To clarify I think the pressure in the krausening or second ferment drives 4vg.

The isoA I believe is influenced by the access to oxygen through the growth phase. ie open ferm.


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I don’t notice any extra clove and I spund to 4vol. 


I don’t follow the second.  The head space of the fermenter is full of oxygen for at least a day after pitching due to the nature of gas mixing laws. Also if you oxygenate with pure o2 it’s in the liquid as well.  Active yeast will consume all o2 injected within 2 hours of pitching (verified with a DO meter).  The water column pressure on an airlock is pretty much null as well.  So not sure on that. 


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[hackrsackr]

Hmm... may want to revisit that hypothesis. Esters come from growth. The access to oxygen keeps a small pitch of yeast in the growth phase longer.


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[Robert]

To clarify I think the pressure in the krausening or second ferment drives 4vg.

The isoA I believe is influenced by the access to oxygen through the growth phase. ie open ferm.


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IsoA and 4VG are both fermentation byproducts of specific yeasts, and yeasts with a propensity to produce them can be influenced to do so in various ways.  With respect to isoA  temperature and oxygenation can drive it to a limit set by the available glucose; to surpass that limit more glucose is needed: enter the downward mash program.  The same can be said of 4VG; temperature and oxygenation can influence production but the limiting substrate is ferulic acid, produced at 114°F.

[JJeffers09]

Hmm... may want to revisit that hypothesis. Esters come from growth. The access to oxygen keeps a small pitch of yeast in the growth phase longer.


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Esters come from precursors in the mash, that honestly get metabolized and dispelled in the lag phase IIRC, I need a point of reference but I'm in a hotel waiting room.

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[hackrsackr]

Yeast create biomass with the access to oxygen, aerobic fermentation. Anaerobic fermentation produces alcohol and co2.


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[hackrsackr]

To clarify I think the pressure in the krausening or second ferment drives 4vg.

The isoA I believe is influenced by the access to oxygen through the growth phase. ie open ferm.


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IsoA and 4VG are both fermentation byproducts of specific yeasts, and yeasts with a propensity to produce them can be influenced to do so in various ways.  With respect to isoA  temperature and oxygenation can drive it to a limit set by the available glucose; to surpass that limit more glucose is needed: enter the downward mash program.  The same can be said of 4VG; temperature and oxygenation can influence production but the limiting substrate is ferulic acid, produced at 114°F.

Not arguing any of that. Just saying that the 114 rest in a standard mash does not make glucose. That’s all.


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