Please explain some cider additives.

I've been doing a whole lot of reading here and some books and have come across many mentions of chemical additives that are used for one reason or another.
I think that I know a few but would appreciate any info that you wish to share.
P.S. I didn't do well in chemistry so please be patient with me.
Please help me with definitions for the list below:

Potassium metabisulfite –
Sodium metabisulfite –
Sulfur Dioxide – Yeast and bacteria killer, antioxidant and Acetification prevention (Don’t use pre-fermentation in a high acid cider) (Not needed if juice is pasteurized)
Pectic enzyme – Clarifier, helps coagulate pectin so it will drop out of suspension.
Yeast nutrient – Self-explanatory (Raisins or banana?)
Potassium sorbate - used to stop fermentation. you don’t need it If you're going to carb, if you're bottling still, you don't need it unless you back-sweeten with a fermentable sugar.
Potassium Carbonate – Increases pH
Calcium carbonate – Increases pH
Malic acid – lowers pH and has a very tart taste.
Wine tannins and Acid blend – palate enhancers
Tartaric acid - a little softer taste (and will also drop out in cold storage to some extent).
Lactic acid - has a "softer" taste to it.
Citric acid -

PME - pectin methyl esterase?
Yeast energizer - ?
Potassium Chloride - ?
Calcium Chloride - ?
Sodium Sulfate - ?
Tartaric acid - ?
DME - ?

Does our basic info help at all? https://www.homebrewtalk.com/showthread.php?t=508303

I have made about a half dozen hard ciders and I just use yeast and sometimes some brown sugar. When I make a beer and ciders I try to go all natural.

Yes Yooper, the additive and Sulfite section was a good basic intro.

CMcPherson said:

I've been doing a whole lot of reading here and some books and have come across many mentions of chemical additives that are used for one reason or another.
I think that I know a few but would appreciate any info that you wish to share.
P.S. I didn't do well in chemistry so please be patient with me.
Please help me with definitions for the list below:

Yeast nutrient – Self-explanatory (Raisins or banana?)
Potassium metabisulfite – Yeast killer and antioxidant (only if juice is not pasteurized?)
Sodium metabisulfite – Yeast killer
Sulfur Dioxide - Yeast and bacteria killer and Acetification prevention (Don’t use pre-fermentation in a high acid cider)
Potassium sorbate - inhibits yeast reproduction
Pectic enzyme – Clarifier, helps coagulate pectin so it will drop out of suspension
Wine tannins and Acid blend – palate enhancers
Calcium carbonate – Increases pH
Malic acid – lowers pH
Potassium Carbonate – Acetification prevention
PME - (pectin methyl esterase?)
PBW – Cleaning agent?
Yeast energizer - ?
Potassium Chloride - ?
Calcium Chloride - ?
Sodium Sulfate - ?
Tartaric acid - ?
Sorbate - ?
DME - ?

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Potassium metabisulfite, Sodium metabisulfite, Sulfur Dioxide
These are all for the same pupose, to kill unwanted microbes in your cider and to act as an antioxidant. You can use it prefermentation to kill those unwater bugs and it will also protect a pasteurized cider from the introduction of bugs and as an antioxidants. Its not going to kill your commercial yeasts at normal doses.

Pectic enzyme diegest pectins into little bits, not coagulating them.

Potassium and Calcium carbonate both increase pH, they have nothing to do with preventing acetification, which is caused by bacteria that you can kill with those sulfites.

Potassium sorbate is sorbate here, inhibits yeast division. but, it can be eaten by bacteria and make a nasty geranium smell supposedly, we make most of our ciders dry so we dont worry about adding sorbates.

Keep up the studies, you are making progress. WVMJ

I updated the list in my original post reflecting your corrections.

WVMJ said:

Potassium metabisulfite, Sodium metabisulfite, Sulfur Dioxide
These are all for the same pupose, to kill unwanted microbes in your cider and to act as an antioxidant. You can use it prefermentation to kill those unwater bugs and it will also protect a pasteurized cider from the introduction of bugs and as an antioxidants. Its not going to kill your commercial yeasts at normal doses.

Click to expand...

Bugs...? do you mean fruit flies?

"Its not going to kill your commercial yeasts"
But it does kill natural yeast correct?

WVMJ said:

Pectic enzyme diegest pectins into little bits, not coagulating them.

Click to expand...

It's used as a clarify cider though correct?

Are the Malic, Tartaric, Citric and Lactic acid combined to make the Acid Blend that is used for flavor enhancement?

Not bug bugs, bacteria et al, and Most but not all wild yeasts, commercial yeasts are still natural just not wild anymore. Pectinase eats pectin, so it clears ciders and wines. No lactic in commerical acid blends, usually a different ratio of Tartaric, Malic and Citric. Keep up the hard work on your studies and keep asking questions. WVMJ

I just got my copy of New Cider Maker's Handbook so all y'all will get a break while I study that for a while.