"Tom" > wrote:

> Have Gewurtz we picked Sunday, (Portland, OR)
>
> Here are specs after pressing.
>
> Brix 25
> TA .60
> PH 3.8
>
> I need to get the acid up a bit and instructions indicate I need about 1
tsp
> acid blend per gallon to raise .15. So in this case 11 gallons juice
would
> need 3.6 tablespoons (I promise my next investment is a scale)
>
> Just would like confirmation that I am understanding this right. Shooting
> for about .75 TA

Sounds like you got it right.

Teaspoons to add = (TargetTA - MeasuredTA) / .15 x US Gallons = (.75 - .60)
/ .15 x 11 = 11

Tablespoons to add = Teaspoons to add / 3 = 11 / 3 = 3.67

If you use a scale, the formula (according to the same test kit
manufacturer) is:

Ounces to add = (TargetTA - MeasuredTA) / .15 x US Gallons / 6

Grams to add = (TargetTA - MeasuredTA) / .15 x US Gallons x 4.725

The difficulty with using units-of-volume to measure dry chemicals is that
there is a significant difference in weight per unit-of-volume between
powder and crystals, between different sized powders or crystals, between
newly poured and "settled" substances, and between dessicated and hydrated
substances.

For example, the Carlson kit says 1 teaspoon of acid blend will effect a
..15% increase in one (US) gallon, and that 1 ounce will effect the same
increase in 6 gallons. Thus they consider a teaspoon to weigh 1/6 ounce or
4.725 grams (from whence the values in my second set of formulae). I assume
this is true of the acid blend produced by Carlson. However, my supplier
says 1 teaspoon will effect a .12% increase in one US gallon, and Presque
Isle's table shows 5 grams per teaspoon for acid blend.

Also, whether measuring dry or wet substances, it is tricky to get the same
(or correct) amount in each teaspoonful.

So, a scale is indicated where precision is required. Teaspoons are fine
where approximations are sufficient.

eBay is a good place to find a low-priced high-quality NEW gram scale. I
bought a 6-lb capacity scale accurate to +/- 1 gram for less than $30, which
I now use for all my chemical additions.