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Mash pH


bcoutts

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Seeking help with my mash profile.  After heating and holding the mash (all wheat) and adding the alpha enzymes my pH is above 6.2.  I know this is the high end for alpha but the enzymes seemed to work well (no starch).  I added some citric acid to get the pH down but after adding 300g the pH had only dropped to 5.6 - still above the beta-amylase sweet spot.  I am using carbon filtered city water - any ideas of how to get the mash pH down to where the betas would be happy?  Thanks.

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You want to hit the sweet spot for the specific enzyme you are using, both for temperature, pH, and efficiency without denaturing. As the chemical reactions and breakdowns/conversions take place you will have fluctuations in your pH. It's normal to add acid at multiple times throughout a mash.

Your other enzymes might also work well over long periods of time (throughout the fermentation) and the pH will probably get into their effective range.  Keep in mind that if you drop your pH too low, when the yeast kick off you'll need to raise it up to avoid stressing/killing the yeast.

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5-10% backset/stillage.  This generally gets us close to the ballpark, with only small additions of citric being necessary to adjust our large batch volumes (2000l).  Our water is a little bit on the alkaline side and on the hard side, so it would require larger acid adjustments.

 Find a local chemical supplier and buy USP citric from them, you'll probably pay less than $2 a pound.

 

 

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  • 4 weeks later...

On the novazymes spec sheet I have, it suggests sulfuric acid as an adjuster. Is that an option? I seem to have some difficulty with the idea. If sulfuric is an option, I wonder about something like formic acid or oxalic both of which are also natural and poisonous, but are much easier to get and manage. Thoughts?

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Formic Acid is a carboxylic acid that can form an ester with ethanol - ethyl formate.  This might have potential flavor implications for the distillate.  Has a rummy, winey, cognac, heady aroma.

Sulfuric may have implications as well.  In the old Arroyo papers, he utilizes sulfuric acid to adjust pH for his heavy rums.  I often wondered if the reason was simple economy, inexpensive and smaller quantities needed, or if using sulfuric acid drove higher levels of ester formation during distillation, as would be characteristic of the style.   Mineral acids like sulfuric are Fischer Esterification catalysts during reflux, and can drive higher levels of ester creation during distillation.

 

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  • 2 weeks later...
On 1/11/2019 at 5:05 AM, Silk City Distillers said:

You have a source for this?

SF Spirits comp judges feedback on a brand I consulted for in 2016 (Brandy). Upon receiving that feedback that I had also never heard before I delved deeper into the google and found this from pg 10 of Bergland's Artisan Distilling: a Guide for Small Distilleries (2004). ""The bacterial decomposition of citric acid leads to formation of lactic acid, acetic acid, formic acid, and acetaldehyde which can be detrimental to the mash and can appear in the resulting distillate."" Section is on fruit fermentation, not all wheat, but that's what I have for you.

 

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Yeah, interesting, since citric acid is naturally present in grapes, naturally present in cane juice or molasses, and even present in grain based beers - due to citric acid being produced by yeast during the initial stages of fermentation (Krebs/TCA Cycle).  Not to mention that all four of the noted metabolites have numerous pathways for production, and typically exist in every fermentation, regardless if citric is dosed or not.

Saying backset is better than citric is odd (though I'd agree, but for more reasons than just acidity), because backset is going to be choc-full of the same exact organic acids, lactic, acetic, formic, butyric, propionic, that the particular judge would identify as a fault.

Single greatest impact to acetaldehyde is fermentation temperature and yeast strain.  Great study by Chris White looked at fermentation temperature, same wort, same yeast, fermented at 66f and 75f.  The slightly higher temperature fermentation produced 10x the acetaldehyde.  Less so would be distillation prior to the completion of fermentation, acetobacter infection (fruit flies), oxidation post fermentation, etc.

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On 1/25/2019 at 9:07 AM, SlickFloss said:

SF Spirits comp judges feedback on a brand I consulted for in 2016 (Brandy). Upon receiving that feedback that I had also never heard before I delved deeper into the google and found this from pg 10 of Bergland's Artisan Distilling: a Guide for Small Distilleries (2004). ""The bacterial decomposition of citric acid leads to formation of lactic acid, acetic acid, formic acid, and acetaldehyde which can be detrimental to the mash and can appear in the resulting distillate."" Section is on fruit fermentation, not all wheat, but that's what I have for you.

 

Can also testify to this. Specific strains of lactobacillus will break citric acid down into diacetyl which is very undesirable for distillates that require grace, such as gin and fruit brandy. For this reason, fruits to be fermented spontaneously or controlled fermentations to be stored for a long time should never be picked in anything less than a fully ripe state; fruits that are unripe contain higher levels of citric acid.

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On 1/30/2019 at 4:04 PM, MDH said:

Can also testify to this. Specific strains of lactobacillus will break citric acid down into diacetyl which is very undesirable for distillates that require grace, such as gin and fruit brandy. For this reason, fruits to be fermented spontaneously or controlled fermentations to be stored for a long time should never be picked in anything less than a fully ripe state; fruits that are unripe contain higher levels of citric acid.

I have found this to be essential for nuanced flavor...... We actually have found that making wine from grapes picked at night instead of during the day actually matters big time in the brandy end result...... Which I find just absolutely captivating.

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On 1/26/2019 at 6:22 AM, Silk City Distillers said:

="Single greatest impact to acetaldehyde is fermentation temperature and yeast strain.  Great study by Chris White looked at fermentation temperature, same wort, same yeast, fermented at 66f and 75f.  The slightly higher temperature fermentation produced 10x the acetaldehyde.  Less so would be distillation prior to the completion of fermentation, acetobacter infection (fruit flies), oxidation post fermentation, etc."

That figure is staggering I am going to find that material to peruse, thanks for the reference..... We pitch super low but let em finish high on our Ryes, I am going to look at holding temp vs our current method

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On 2/1/2019 at 2:56 PM, MDH said:

Indeed... Brandy, in my opinion, is the most under explored and under appreciated spirit in North America --- so much nuance. There was big anticipation for it being the next single malt obsession, but ultimately, no social context exists to support brandy in the same way Whisky has so many connotations for masculinity, the toasting of moments, unwinding after a day, etc.

Brandy is still mostly stuck in the world of wealth signalling and stuffy french Grandfathers, with a few exceptions. So it remains brand-driven and mostly recognized as just "Cognac", with "Cognac" meaning just Hennessey and Courvoisier. Whiskey, on the other hand, is now categorially driven, with people keen to explore every corner of single malt possible. What power do we have, if any, to shift brandy in that direction?

Anyway, I am derailing this thread. But it really warrants discussion.

Luckily the great state of Wisconsin appreciate's Brandy more than any other spirit.

 

Start a new thread and lets run wild with it. Tag me in bro!

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On 2/1/2019 at 4:46 PM, Silk City Distillers said:

Ordered some phosphoric from my chem supply.  Will compare.

Please report back on efficacy amigo.

 

As per your other comments, I have an interesting conundrum in which I am trying to make highly estered bourbon for a rebarreling experiment. 

On 1/11/2019 at 4:17 AM, Silk City Distillers said:

Formic Acid is a carboxylic acid that can form an ester with ethanol - ethyl formate.  This might have potential flavor implications for the distillate.  Has a rummy, winey, cognac, heady aroma.

Sulfuric may have implications as well.  In the old Arroyo papers, he utilizes sulfuric acid to adjust pH for his heavy rums.  I often wondered if the reason was simple economy, inexpensive and smaller quantities needed, or if using sulfuric acid drove higher levels of ester formation during distillation, as would be characteristic of the style.   Mineral acids like sulfuric are Fischer Esterification catalysts during reflux, and can drive higher levels of ester creation during distillation.

 

I wonder if utilizing sulfuric and or formic for adjustment (likely in conjunction with backset) would help provide more of that heady bouquet for us to pull out

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