Acid adjustment post primary fermentation

Discussions and questions (vintages, winemaking, etc) for those ITB. All are welcome to post.
Post Reply
Message
Author
User avatar
Tim Corliss
Posts: 1233
Joined: February 13th, 2009, 9:14 pm

Acid adjustment post primary fermentation

#1 Post by Tim Corliss » February 4th, 2018, 12:15 am

Has anyone made an acid adjustment post primary fermentation? Curious to hear peoples experience

I’ve heard that if this is done, the acid adjustment sticks out like a sore thumb. True?
ITB

User avatar
Brian Tuite
GCC Member
GCC Member
Posts: 18531
Joined: July 3rd, 2010, 8:53 am
Location: Podunk CA

Acid adjustment post primary fermentation

#2 Post by Brian Tuite » February 4th, 2018, 6:41 am

Why would someone want to adjust before malo.
Bob Wood - 1949-2013 Berserker for eternity! RIP

"On self-reflection, I think a big part of it was me just being a PITA customer..." ~ Anonymous Berserker

"Something so subtle only I can detect it." ~ Randy Bowman

2019 WOTY...

User avatar
Ken Zinns
GCC Member
GCC Member
Posts: 3447
Joined: March 11th, 2009, 4:53 pm
Location: Oakland, CA

Acid adjustment post primary fermentation

#3 Post by Ken Zinns » February 4th, 2018, 6:48 am

Tim Corliss wrote:Has anyone made an acid adjustment post primary fermentation? Curious to hear peoples experience

I’ve heard that if this is done, the acid adjustment sticks out like a sore thumb. True?
As noted, if you're going to make an acid (or water) adjusment, it's preferable to do it during fermentation. I've made small post-fermentation acid adjustments to a couple of my own non-commercial wines in the past, but I think the key is to do them soon after primary and ML (give the wine max. time to integrate the acid in barrel or tank before bottling) and not to make too large an adjustment (I've adjusted 1g/L or less). The ones I made adjustments to were done in December or early January following crush. I've never felt the acid on those wines stuck out and never had anyone mention that to me either.
ITB, Harrington Wines & Eno Wines, and Grape-Nutz.com

Wes Barton
GCC Member
GCC Member
Posts: 3305
Joined: January 29th, 2009, 3:54 am

Acid adjustment post primary fermentation

#4 Post by Wes Barton » February 4th, 2018, 3:21 pm

Brian Tuite wrote:Why would someone want to adjust before malo.
I suppose if the numbers are way off and you know an add is needed, that gives more time to integrate. Of course it would still be wise to err on the side of caution, since working out the math only gives you numbers, not perceptual balance. If you're dealing with the same fruit year after year that always needs an add, you might "just know" how much to add in a given year and ace it every time.
ITB - Useless lackey

Eric Lundblad
BerserkerBusiness
BerserkerBusiness
Posts: 1625
Joined: January 28th, 2009, 2:36 pm

Acid adjustment post primary fermentation

#5 Post by Eric Lundblad » February 4th, 2018, 10:08 pm

Brian Tuite wrote:Why would someone want to adjust before malo.
It's not so much adjusting before malo, but there's a benefit to adjusting acid prior to the bitartrates precipitating out of solution.

Bitartrates (potassium bitartrate, i.e. tartaric acid + potassium) are more soluble in a water solution than an alcohol solution...so sometime after fermention (primary) is finished some of the tartrates will precipitate out (this happens with reds and whites). When this happens, the pH will either go up or go down...if the pH is below ~3.95 when the tartrates precipitate out then the pH will go down. If the pH is above 3.95 the the pH will go up. I know, it's odd. The pH used to be believed to be 3.65...turns out that's the number for tartrates in a water solution. It's higher (~3.95) when alcohol is involved. Roger Bolton, UC Davis, reported this a long time ago, but everyone mostly ignored him on this. Anyways, the lower the pH is, below 3.95, the more the pH will drop when tartrates precipitate (or the more the pH is above 3.95, the more it will go up). I know this sounds a bit like a tax plan that congress just approved, but it's true!

Anyways, if you acidify prior to the tartrates precipitating (during or right after fermentation, effectively) then you'll get a much larger drop in pH than if you waited and acidified later. On the other hand, over acidifying is never a good thing, so waiting until ML is done is always a good/safe option. Or pick earlier, if you can.
Ladd Cellars
Winemaker & Owner

User avatar
Brian Tuite
GCC Member
GCC Member
Posts: 18531
Joined: July 3rd, 2010, 8:53 am
Location: Podunk CA

Acid adjustment post primary fermentation

#6 Post by Brian Tuite » February 5th, 2018, 5:46 am

Wes Barton wrote:
Brian Tuite wrote:Why would someone want to adjust before malo.
I suppose if the numbers are way off and you know an add is needed, that gives more time to integrate. Of course it would still be wise to err on the side of caution, since working out the math only gives you numbers, not perceptual balance. If you're dealing with the same fruit year after year that always needs an add, you might "just know" how much to add in a given year and ace it every time.
Eric Lundblad wrote:
It's not so much adjusting before malo, but there's a benefit to adjusting acid prior to the bitartrates precipitating out of solution.

Bitartrates (potassium bitartrate, i.e. tartaric acid + potassium) are more soluble in a water solution than an alcohol solution...so sometime after fermention (primary) is finished some of the tartrates will precipitate out (this happens with reds and whites). When this happens, the pH will either go up or go down...if the pH is below ~3.95 when the tartrates precipitate out then the pH will go down. If the pH is above 3.95 the the pH will go up. I know, it's odd. The pH used to be believed to be 3.65...turns out that's the number for tartrates in a water solution. It's higher (~3.95) when alcohol is involved. Roger Bolton, UC Davis, reported this a long time ago, but everyone mostly ignored him on this. Anyways, the lower the pH is, below 3.95, the more the pH will drop when tartrates precipitate (or the more the pH is above 3.95, the more it will go up). I know this sounds a bit like a tax plan that congress just approved, but it's true!

Anyways, if you acidify prior to the tartrates precipitating (during or right after fermentation, effectively) then you'll get a much larger drop in pH than if you waited and acidified later. On the other hand, over acidifying is never a good thing, so waiting until ML is done is always a good/safe option. Or pick earlier, if you can.
Thanks guys, interesting reading. [cheers.gif]
Bob Wood - 1949-2013 Berserker for eternity! RIP

"On self-reflection, I think a big part of it was me just being a PITA customer..." ~ Anonymous Berserker

"Something so subtle only I can detect it." ~ Randy Bowman

2019 WOTY...

Post Reply

Return to “Cellar Rats (ITB)”