New PH meter and Sulfate

[homer]

Testing the wine with the PH tester and following the chart in HWD(Home Winemaking for Dummies) I am getting some different amounts of Sulfate than what the kit suggest to add.
Example; Australian Shiraz/Viognier has a of PH 3.60 HWD suggests 30 to 50 PPM which at 50 PPM that only equals 1.60 grams the kit package contained 5.5 grams.
Am I missing something? bk

 

[djrockinsteve]

I have not done a kit but testing for sulfites in wine needs to be done with a titration kit, not a ph tester. Use your ph tester for ph and for acid levels with the aide of Sodium Hydroxide.

You will need Potassium Metabisulfite at the end of fermentation, and each time you rack. As time goes on you will use less and less.

Could your kit include extra for sanitizing your instruments? Just some idea. At bottling t is recommended you have 30ppm of sulfite.

Others will hop in and help, hang on.

 

[homer]

Well all I can say is "Appendix D" in the HWD thinks you can base your SO2 on PH. bk

 

[ibglowin]

How are you actually testing for sulfite?

You need to add the entire package of sulfite that came with the kit first, then test for FREE Sulfites. The sulfite will react with any Oxygen in the wine and turn into BOUND sulfite (SO3). That is now out of the equation and unavailable to protect your wine anymore.

The reason you add more than is actually necessary up front is after you add that pack, your going to lose about 55% immediately and only have half that left as FREE sulfite to protect the wine down the road.

You CAN base the amount of sulfites needed in a wine based on pH.

The lower the pH of the wine, the less amount of free sulfite is necessary to protect to wine.

But you can't figure out how MUCH sulfite is in a wine based on pH. For that you still need to do an analysis for free sulfites.

 

[BobF]

Well all I can say is "Appendix D" in the HWD thinks you can base your SO2 on PH. bk

I feel pretty certain (I don't have the book) that the chart is telling you how much free so2 is required to achieve the desired molecular so2 level; usually .8mg/L.

Molecular so2 level for a given free so2 level is tied directly to pH.

 

[homer]

If PH is not the correct way to determine quantity of SO2 to add where can I find the charts for SO2 addition based on TA? bk

 

[ibglowin]

Here is a handy dandy Sulfite Calculator. Doesn't get any easier than this.

You have to know:

Your pH, your current level of SO2, your desired level of SO2 and your volume. Enter all the values and it will tell you exactly how much to add.

 

[BobF]

If PH is not the correct way to determine quantity of SO2 to add where can I find the charts for SO2 addition based on TA? bk

pH *IS* the correct way to determine the target SO2 level.

Kits contain a fixed amount so that they cover all of the bases. There will be natural variations due to the differences between the various winemakers that use their kits.

The fact that the kit contains a packet with 5.5g of sulfite doesn't mean that 5.5g will always be the correct amount to add.

It is common practice to add more than testing indicates in the first addition of SO2 b/c in the first addition there are a lot of unbound SO2 binders in the wine.

I would add the packet according to the kit instructions and test again either at the next racking or at 3 mos, whichever comes first.

The folks that make the kits go through a lot of research and testing to ensure consistent results for the majority - most kit makers don't do exaustive testing, they follow the kit instructions.

If you opt to only add the amount called for according to your test results, test again in a month to see if it needs more and add as necessary.

 

[djrockinsteve]

Here is an estimate. The calculator is good.

Ph of your________Free SO2 Needed To Protect Wine__% That Is Molecular
Wine____________(As expressed as mg per litre)
3.0_____________13______________________________6. 1
3.2_____________21______________________________3. 9
3.4_____________32______________________________2. 5
3.6_____________50______________________________1. 6
3.8_____________79______________________________1. 0
4.0_____________125_____________________________0. 6

As you can see as your ph rises, so does the need for additional sulfite to protect your wine.

 

[BobF]

This might be easier to read:
http://www.foodsci.purdue.edu/research/labs/enology/FreeSO2(pH)Pro.pdf

 

[ibglowin]

And of course we can muddy up the waters even more by stating that there are generally 2 dose levels of Sulfite. One for reds and a different (higher dose rate) for whites.

Whites are dosed at 0.8 mg/L and reds are dosed at a lower 0.5mg/L. Reason being if not obvious is that white wines are more prone to oxidation than red wines.

Here is yet another Sulfite Level Chart based on those dose rates.

Who said wine making was easy?

 

[robie]

Ugh! I'm getting a headache just trying to keep up with this thread!!!

 

[BobF]

And of course we can muddy up the waters even more by stating that there are generally 2 dose levels of Sulfite. One for reds and a different (higher dose rate) for whites.

Whites are dosed at 0.8 mg/L and reds are dosed at a lower 0.5mg/L. Reason being if not obvious is that white wines are more prone to oxidation than red wines.

Here is yet another Sulfite Level Chart based on those dose rates.

Who said wine making was easy?

I'm not sure I agree with a .5mg/L level for reds. Sulfite isn't all about oxidation.

Every study on SO2 I've read recommends .8mg/L for ALL wine to ensure proper suppression of microbial activity.

 

[ibglowin]

They use 0.8 just because its easier to remember one dosing factor rather than two. The tannins found in red wine are also antioxidants thus the need for less sulfite in reds.

Winemakers should follow follow one path or the other to suit their needs.

Me, I dose based on pH and wine type (color) and err on the low end since I find the smell of sulfite in an open wine a major flaw.

 

[robie]

since I find the smell of sulfite in an open wine a major flaw.

Now that I can understand!!!

I don't know if my nose/taste are becoming more sensitive, but lately, the smell and taste of sulfite in even many commercial wines is so prevalent it is starting affect my enjoyment of the wine.

 

[ibglowin]

I didn't use to I swear but now, I can smell it at 30 paces.....

 

[homer]

I wish I could post the table from the HWD but I think I might be infringing on some touchy copyright laws. It shows target levels in PPM you need at your PH level, then in another Table how many grams to get that target level. The authors theory is, after you test for free SO2 you can add more but you can't take it out. bk