FermCalc - Acidity Calculators - Acid Titration Calculator
- Introduction
- Input Field Definitions
- Output Field Definitions
- Calculation Details
- Acidification & Deacidification
- Introduction
- Input Field Definitions
- Output Field Definitions
- Calculation Details
- Initial acidity is less than the target acidity.
- Initial acidity is greater than the target acidity.
- Amelioration
- Introduction
- Input Field Definitions
- Output Field Definitions
- Calculation Details
- NaOH Standardization Calculator
- Introduction
- Input Field Definitions
- Output Field Definitions
- Calculation Details
## Acid Titration Calculator## IndroductionThe Acid Titration Calculator determines the titratable acidity (TA) of a wine sample given the volume of the sample and the volume of sodium hydroxide (NaOH) added during a titration test. ## Calculation Details
Acid titration makes use of the neutralization reaction between NaOH and the acids
present in wine. In this reaction, the OH
where
The mass of the acid in solution is simply the acidity multiplied by the volume or:
where
Combining equations (1) and (2) and solving for acidity we get:
By titrating for acidity, all we've really determined is the number of available
H i is equal to 2, so equation (3)
becomes:
_{a}Back to top ## Acidification & Deacidification Calculator## IndroductionThe Acidification & Deacidification Calculator determines the amount of a selected acid or deacidifier required to increase or decrease the acidity of a wine from its current value to some target value. If the target acidity is greater than the initial acidity, a list of acids will be shown. If the target acidity is less than the initial acidity, a list of deacidifiers will be shown. Acid blend is assumed to be a blend of 40% tartaric, 40% malic, and 20% citric acids. ## Calculation DetailsThere are two scenarios we need to consider for this calculation. - Initial acidity is less than the target acidity.
- Initial acidity is greater than the target acidity.
For the first scenario, FermCalc will calculate the amount of acid required to increase the acidity to the specified target. For the second case FermCalc will calculate the amount of deacidifier to add. If you are diluting a must with water, blending juices, or blending wines to adjust acidity, use the Blending Calculator to calculate the proportions required to achieve the desired acidity. Back to top## Case 1: Initial Acidity is Less Than the Target AcidityFor this case we'll be adding acid to increase the acidity. FermCalc first converts the initial and target acidity values to the tartaric reference using the conversion factors explained in the Acidity Conversions discussion.
To calculate the required addition of the selected acid we need to write a molar
balance equation for the H
where
Rearranging to solve for the mass of acid to add we get:
Values of molecular weight and number of H
For Acid Blend, the composition is assumed to be 40% tartaric, 40% malic, and 20% citric acids. Back to top## Case 2: Initial Acidity is Greater Than the Target Acidity
For this case we'll need to add a deacidifier such as calcium carbonate (CaCO
Note that KOH is not authorized by the Alcohol and Tobacco Tax and Trade Bureau (TTB) for treatment of wine or juice, so it cannot be used by commercial wineries. But that shouldn't stop amateur winemakers from using it.
To calculate the required amount of any of these additives, we need to know their
molecular weights as well as the number of H
We can calculate the required mass of deacidifier to add by balancing the initial
and final quantities of H
where
Solving for the amount of acid reducer we get:
Based on equation (12) above, FermCalc calculates the following addition rates to reduce acidity by 0.1% (1 g/l) tartaric.
For additional information on using these additives, see this article by Bill Collings. Back to top## Amelioration Calculator## IntroductionAmelioration is the dilution of must with water in order to reduce the acidity or sugar content. When diluting to reduce the acidity, it is often necessary to add sugar to maintain the potential alcohol level of the must. When diluting to reduce sugar content, it is often necessary to add acid to bring the acidity up to an acceptable level. The Amelioration Calculator determines the required additions of water, sugar, and acid to a must to meet the desired acidity and SG levels given the initial acidity, initial SG, and initial must volume. Alternatively, the target must volume can be specified, in which case FermCalc calculates the initial volume of must required, along with the required water, acid, and sugar additions. ## Input Field DefinitionsAcid Type – The type of acid being added, either tartaric, malic, citric, or acid blend. Acid blend is assumed to be a blend of 40% tartaric, 40% malic, and 20% citric acids. Target Acidity – The desired acidity of the must after the water/sugar/acid additions. Range: 0 to 100 grams/liter. Initial Acidity – The acidity of the must prior to the water/sugar/acid additions. Range: 0 to 100 grams/liter. Target SG – The desired specific gravity of the must after the water/sugar/acid additions. Range: 0.77193 to 1.55454 Initial SG – The specific gravity of the must prior to the water/sugar/acid additions. Range: 0.77193 to 1.55454 Must Volume – The volume of the must prior to the water/sugar/acid additions. Target Volume – The desired volume of the must after the water/sugar/acid additions. ## Output Field DefinitionsWater Required – The volume of water required to meet the target acidity, SG, and volume. Sugar Required – The mass of sugar required to meet the target acidity, SG, and volume. Acid Required – The mass of acid required to meet the target acidity, SG, and volume. Resulting Volume – The volume of the must after adding the water, sugar, and acid. Reported only if Must Volume is selected above. Must Required – The volume of the juice required to meet the target acidity, SG, and volume. Reported only if Target Volume is selected above. ## Calculation DetailsFermCalc first determines whether the acidity adjustment or the sugar adjustment requires the larger increase in volume. The increase in volume due to the acidity adjustment is calculated from the acid balance equation:
where:
Solving for
Or if we're solving for
The increase in volume due to the sugar adjustment is calculated using the sugar mass balance equations:
where:
If the target (final) SG is greater than or equal to the initial SG, then we won't be
adding any water for the sugar adjustment, so m, substitute it into equation (16),
and re-arrange to solve for _{sa}v, we get:
_{f}
Or if we're solving for
If the target SG is less than the initial SG, then we won't be adding sugar, so
v, we get:
_{f}
Or if we're solving for
The value of v,
its value is taken as the minimum value calculated by equations (15), (19), and (21).
Now that we know both _{i}v and _{i}v,
we can solve equation (16) for the mass of sugar to add, or:
_{f}
Knowing the amount of sweetener to add we can then re-arrange equation (17) to solve for the amount of water to add:
The amount of acid to add is then calculated by modifying equation (6) above as: Back to top ## NaOH Standardization Calculator## IntroductionStandardization is the process of testing a solution of unknown concentration with a solution of a known, precise concentration. The NaOH Standardization Calculator determines the normality of your sodium hydroxide (NaOH) solution from the titration of a potassium hydrogen phthalate (KHP) solution of known normality.
There are a number good reasons to test your solution of sodium hydroxide (NaOH)
prior to titrating your wine. First, NaOH solutions lose strength over time due
to exposure to CO ## Input Field DefinitionsKHP Volume – The volume of KHP solution being titrated. KHP Normality – The normality of the KHP solution being titrated. Volume of NaOH Added – The volume of NaOH solution required to reach the titration endpoint. ## Output Field DefinitionsNaOH Normality – The calculated normality of the NaOH solution. ## Calculation DetailsThe reaction equation for the standardization titration is.
Since KHP reacts with NaOH in a simple 1:1 stoichiometric ratio, we can write the following molar balance:
where
Rearranging equation (26) to solve for the NaOH normality gives:
To perform the standardization titration, measure a small volume (5-10 mL) of the KPH into a water glass or flask. Add about 5 drops of phenolphthalein indicator to the sample. Titrate with your NaOH until the end is reached, which is the first pink blush that persists for at least 20 seconds after mixing the sample. Make note of how much NaOH was used, and enter the values into FermCalc to determine the normality of your NaOH. Back to top
© 2007-2020 Steve Gross |
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