Math geeks - calculating acid additions

[Maylar]

I'm embarrassed that I'm having a brain fart figuring out something that should be simple math. Need a bit of help here.

I want to do an acid adjustment on a mead, by taste. Starting with a 10% solution (5 grams in 50 ml) how much do I need to add to each 25 ml taste sample to increase TA by .01%?

Thanks

 

[RPh_Guy]

That's a pretty small adjustment.

0.01% is 0.01g/100mL, so to adjust a 25mL sample you need 0.0025g.
(Math: 0.01g / 100mL * 25mL = 0.0025g)

Now we can convert that to mL based on your stock solution.
0.0025g * 50mL / 5 g = 0.025mL

That's much too strong of a stock solution to be making such tiny adjustments in such a small sample. I'm thinking you want to adjust by 0.1%, in which case it's 0.25mL of the same stock solution per same sample size. I imagine it would be difficult to taste a difference with smaller adjustments.
You could dilute your stock solution by 10-fold if you want to adjust by 0.01% by adding 0.25mL, easy peasy.

Hope this makes sense.

 

[Maylar]

Thanks.

My experience with cider is that 0.1% is a lot. Like, from 0.5% to 0.6%. That's why I picked .01% as the increment. People typically adjust using an eyedropper, I think one drop is .05 ml. I also have a small syringe with 0.1 ml markings. So if I wanted 0.1 ml to be 0.01% in a 50 ml sample, what should my stock solution be?

 

[RPh_Guy]

Fair enough. I don't have any experience adjusting acid scientifically like this in wine, so I'll take your word for it.

If you have an accurate scale you can calibrate your dropper. While counting, use your dropper to add distilled water (room temp) until you get to 5 grams. Divide the number of drops by 5 to get drops per mL.
A micropipette is the best tool for the job though. Precision is important when you're scaling up by such a large factor.

So if I wanted 0.1 ml to be 0.01% in a 50 ml sample, what should my stock solution be?

I can do this all day
0.01g / 100mL * 50mL = 0.005 g acid needs to be added to your sample.
So, your stock solution needs to be 0.005g per 0.1 mL
That scales to 5 grams per 100mL.

If you know the precision level of your scale (listed in the specs) and the maximum percentage of error you're willing to accept, we could calculator the minimum amount of stock solution you need to make.
Cheers

 

[Maylar]

I can do this all day
0.01g / 100mL * 50mL = 0.005 g acid needs to be added to your sample.
So, your stock solution needs to be 0.005g per 0.1 mL
That scales to 5 grams per 100mL.

Thanks, buddy. My scale reads to .01 grams and I trust it. I could use that to verify my syringe, or as you suggested count drops.

Dunno why this seemed so daunting a task - I'm a software engineer and I write code to do multi order polynomials for linearization of pressure transducers.
... but I can't count to five it seems.

This will be scaled up to 4 gallons in the end.

 

[Seamonkey84]

Dunno why this seemed so daunting a task - I'm a software engineer and I write code to do multi order polynomials for linearization of pressure transducers.
... but I can't count to five it seems.

This will be scaled up to 4 gallons in the end.

We all have those moments at times. The other day I sat down to tie up some flies (for fishing), and at the end, I could not remember how to make the final whip knot to secure the thread to the hook. I ended up just using superglue to secure the thread and only tied that one fly.
That glass of wine/mead I was drinking prob didn’t help

 

[Blacksmith1]

Great! Now I have this image of you doing inappropriate things with small insects....

 

[Seamonkey84]

Great! Now I have this image of you doing inappropriate things with small insects....

Well, that’s prob better than if I had mentioned the name of my favorite salmon/trout streamer fly, it’s got a fun name “Montreal wh*re”. I’ve tied up a couple dozen of those