pickle problem - acid turned neutral...

Submitted by R .Lee on 5/11/06 at 11:33 PM. ( )

Here's something weird - I have a 30 gallon vat that I'm pickling 4 coyote hides and a deer cape in, and tonight I pulled the cape out to do some final fleshing before the tan. As I was working I noticed a small area that was on the verge of slipping, and I couldn't for the life of me figure out why (my experience with pickled hides is that they are the least likely to slip in the process and I've never had one that did).

So I made another fresh pickle solution to return the cape to overnight, and just on a whim I did a ph test on the big vat. The ph was neutral (7 or 8)! Just to be sure I then tested the fresh pickle and it was the expected 1 or 2 ph.

So, what would cause a pickle solution to turn? I had the coyotes in a degreaser bath (which is alkaline) but I rinsed them off before I threw them in the pickle. I've degreased hides before pickling and I've never had anything like this happen. BTW I used oxalic acid for this pickle as I am going to crome tan the 'yotes.

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You must check the pH along the way.

This response submitted by The Undertaker on 5/12/06 at 1:01 AM. ( )

Yes, sounds like the soap did the job.

Never just let a pickle go without checking the pH. You have to keep that pH in the correct range.

I have skins in pickles now for almost three years, the first few weeks I checked the pickle.

The last 2 years the pickle has been stable.

Did you add salt

This response submitted by James Parrish on 5/12/06 at 6:59 AM. ( )

Just curious. Salt is used as a buffer in the pickle solution which helps its pH remain stable.

Am I reading this right?

This response submitted by jrosbor on 5/12/06 at 9:10 AM. ( huntersdream3x@hotmail.com )

You used a 30gal vat for four yotes? How many gallons of pickle did you use? What is the vat made of? EXACTLY how much and what did you use to degrease them? What kind of water did you use for the pickle, city, well, is it hard or soft? What kind of salt did you use? Did you forget to add the acid or did you maybe add something else that you thought was acid? How long were they in the pickle for? Hate to ask so many questions but this does sound so weird?

I would like to know

This response submitted by Mike on 5/12/06 at 9:40 AM. ( )

HOw salt acts as a buffer in a pickle solution, when salt water is basic,(alkaline) and adding salt raises the pH?

Chemistry Lesson

This response submitted by James Parrish on 5/12/06 at 10:40 AM. ( )

Salt does not raise the pH of water (or pickle for that matter). I just did an experiment. I measured the pH of plain distilled water and it read 7.0 I then added plenty of salt. I added so much that it would no longer go into solution. Then, I measured the pH again and it was 6.8 So, not only is salt water not alkaline, salt does not raise pH.

To understand how it works you have to know what pH really is. pH stands for power of hydrogen. In order for a solution to be acidic (low pH), there must be lots of hydrogen ions present (H+). When you use an acid like hydrochloric (HCl)for example, it takes more acid to drop the pH than if you use an acid like sulfuric (H2SO4). That's because sulfuric acid has 2 hydrogen atoms per molecule and hydrochloric only has 1.

As an acidic solution sits, if completely protected from outside contaminants, it will remain acidic. However, when contaminants are introduced, the solution immediately begins to break down through neutralization. As neutralization occurs, salts are formed.

When you add salt to a pickle, you are basically dissolving all the salt that the solution can hold (saturation). As the pickle tries to neutralize from contaminants, the ions produced when the salt was dissolved, keep the hydrogen ions from attaching to any free OH- and producing water. This is what a buffer does.

Now, a properly made pickle will still lose its acidity over time. Salt helps slow the process down.

When I mix a pickle, I mix it per the directions and get my pH in the range of 1.5 or so. Then, I add my hides and let them sit, fully immersed in the pickle for an hour or so. Then, I stir the pickle and let it sit for another hour. I then recheck the pH and adjust as necessary.

I like that lesson James

This response submitted by oldshaver on 5/12/06 at 11:53 AM. ( )

Good info. My opinion, the de-grease is the culprit. Just a guess though.

R. Lee

This response submitted by oldshaver on 5/12/06 at 6:12 PM. ( )

Had 5 minutes at lunch, and didnt read your post all the way through. My guess has been withdrawn. It aint the de-greaser.

I'm wondering...

This response submitted by R .Lee on 5/12/06 at 11:47 PM. ( )

if it might not be the degreaser afterall...I haven't really had the problem until I started soaking down skins in Kemsol degreaser. Before that I'd give them a soak in plain old laundry detergent, maybe with some 409 or something added...I have also in the past been able to keep hides in pickle for weeks without problems.

As for the vat, I use plastic rubbermaid containers - the big ones. That way I can get 8 or 10 gallons of pickle and have plenty of room for the hides. BTW when I put the deer cape in fresh pickle it only went up to around 3 in ph so the deer cape wasn't the problem.

I'm on well water, but I also have a $5k water softener and conditioner so I'm working with about as pure water as can be had... if the problem is caused by the Kemsol (it works really well so I'd hate to quit using it) I wonder how I can keep degreased hides for spoiling my pickle?

pickle prob.

This response submitted by ej on 5/13/06 at 5:57 AM. ( toomuchspam.ccc )

are you rinsing well? [at least twice or three times] your acid ain't strong enough. try a better/stonger acid! also check the ph of the well water before and after your 5k conditioner. you must controll all variables. then come on here with the problem..

More on the Salt question!

This response submitted by Bruce Rittel on 5/14/06 at 10:29 PM. ( rittel@mindspring.com )

Salt in your Pickle serves one purpose - to prevent Acid Swelling. without the Salt included, the Acid would draw in Water and the skin would become thick and rubbery. In fact, it could even begin to rupture the fibers bonds. Once Salt was added - and the swelling subsides - the skin could be tanned. But - more than likely the skin will now be very weak and tear like paper once it's finished.


This response submitted by cyclone on 5/15/06 at 9:06 AM. ( )

Regular old NaCl, salt, sodium chloride, table salt etc...cannot, will not, and has never been a buffer for an acid solution or caused a pH change. It will not affect pH one way or the other unless it has some contaminate in it.

Water from a softening system is alkaline, that will cause a pH change. If your degreaser is alkaline, that will also cause a pH change if it is not rinsed properly.

Try rinsing the hides clean after degreasing and then do a vinegar rinse before the pickle.

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