hbg info

Fermenting Do's and Dont's:

>Wort/Must Aeration
Aeration before pitching the yeast is important, oxygen increases yeast-vitality and helps to build up colonies throughout the entire volume of the wort/must in a very short period of time. Aeration can be repeated in the first 12-24 hours after pitching the yeast. Exceptions are high-efficiency yeasts for professional beer production which can be aerated with an aeration-stone for the first 5 days after pitching the yeast.
Far from this special case, aeration after the first 24 hours can cause the wine defect "Oxidation" which is the oxidation of phenols and/or ethanols. This leads to a flattening of the wine, extreme loss of aroma and taste. (See: https://en.wikipedia.org/wiki/Wine_fault#Oxidation)
There are exceptions to the rule not to aerate the wort/must after 24 hours.

>Addition of fruit
Fruit can be added to all worts/musts and has been done for thousands of years. The fruits should be cut into small pieces and all seeds need to be completely removed to prevent toxins from being extracted by the ethanol. (e.g. cyanide from apple and cherry seeds) You can either press or crush the fruit for better extraction but it's not necessary, yeasts will turn the fruit into mush. Pectinase can be used to increase extraction-rate, since the enzymes destroy the cell-walls of the fruit. (Add pectinase at room temperature, too high temperatures destroys the enzymes)
All added fruit should be taken out of the fermenter after a week, since the fruit can start to decay under absence of oxygen and hydrogen sulfide is created. (See: https://en.wikipedia.org/wiki/Wine_fault#Hydrogen_sulfide)

>Amount of sugar
Sugar is the primary source for ethanol-conversion by the yeast but not enough sugar, or too much is bad. Not enough sugar (6°Bx and below) will increase the fermentation-rate in the first 24h so dramatic, that the wine will foam so violently that the foam is pressed through the airlock and make a mess. Too much sugar (30°Bx and more) will increase the osmotic pressure on the yeast which will inhibit yeast activity drastically and even kill the yeast. If you want to create a wine close to or at the tolerance level of a southern yeast like Port, Malaga or Samos (15.5-16.5%ABV), or you want to use a Turbo yeast for distilling (19.5-21%), you should start with a sugar amount of ~17°Bx and feed sugar over time whenever the fermentation activity declines. Check your wort/must for unfermentable sugars before starting.

>Acidity (Unimportant for beer, important for cider/wine)
Acidity is not pH! Acidity is unfortunately something that a lot of homebrewers don't really care for, but they should. Every cider/wine lives from the trifecta alcohol-sugar-acidity, while alcohol and sugar set the stage and the plot, acidity is the soundtrack, it creates what wine-lovers call "body". If you think that your cider/wine tastes "hollow", your acidity might be too low. A wine/cider should always stay in the range of 5-7g/l acid, while strong, heavy wines can profit from higher values like 7.5-8.5g/l but should never go higher than 9g/l. Lactic Acid (80%) and Citric Acid can be used and it's always recommended to use a mix of the two, because high amounts of only one acid can create bad taste and in case of lactic acid can even be harmful for consumption. 3.75g/l lactic acid (80%) should never be exceeded.

>Bottle Pasteurization and Pressure

C_final = C_start + 0.5 * 0.91 * m / V

>C_final = final carbonation in g/l
>C_start = carbonation before bottling in g/l
>m = mass of sugar in g
>V = volume of liquid in l

Since we're always properly stirring the brew before bottling to remove any solved CO2 from the liquid, we can assume C_start to be 0, so we can cross that one out. And since we want to know the amount of sugar to ad per 1 liter, we can cross out V as well. And finally as a rule of thumb we can substitute 0.91 for 1, so we can cross that one out as well.
We end up with:

C_final = 0.5 * m

or in short, you always end up with half the amount of g/l of CO2 of the sugar you added in grams.

For example to get a final carbonation of 4g/l CO2 you need to add 8g of sugar per liter.

To calculate what kind of pressure in Bar we're ending up with, we need to take a look at Henry's Law. Henry's Constant for CO2 solved in water at 298.15K is 0.034 and the solubility of CO2 has a constant value of 2400.

Kh = 0.034 * e^2400 * ((1 / (273 + T)) - (1 / 298))

>Kh = Henry Coefficient
>e = Euler's number
>T = Temperature of liquid in °C

Vm = C_final / 44

>Vm = Volume of CO2 in mol/l

P = (Vm / Kh) - 1

>P = Pressure in Bar (minus 1 Bar atmospheric pressure)

So for our liquid with 4g/l CO2 at 20°C we'll get:

Kh = 0.034 * e^2400 * ((1 / 273 + 20)) - (1 / 298)) = 0.03901
Vm = 4 / 44 = 0.09091
P = (0.09091 / 0.03901) - 1 = 1.33

Our bottle sits at 1.33 Bar at 20°C

Now we want to pasteurize the bottle at 70°C:

Kh = 0.034 * e^2400 * ((1 / 273 + 70)) - (1 / 298)) = 0.01182
Vm = 4 / 44 = 0.09091
P = (0.09091 / 0.01182) - 1 = 6.69

At 6.69 Bar, we're now on our way to the ER.

As a rule of thumb, when using conditioned beer bottles (0.5l) we always want to stay below 5 Bar, which means 3g/l CO2 should not be surpassed, which means to not ferment more than 6g of sugar per liter in the closed bottle.

As an addendum, what I mean by the last sentence is, if you want a carbonated AND backsweetened brew, you need of course to add more than 6g per liter. You just have to make sure to start the pasteurization before more than 6g of sugar per liter are fermented.
You can either build a manometer cap for a flip top bottle to see the exact pressure, or you can bottle your brew in the desired glass bottles, except for one which you fill into a PET bottle. That way you can feel the pressure by squeezing the bottle as well as opening the bottle and giving it a taste for sweetness and carbonation. This is especially important if you don't know for sure that all of the solved CO2 was successfully removed from your brew before bottling, because the amount of CO2 in g/l adds up and thus you'll get a higher real pressure than calculated.
In the end it's a case of doing it 3-4 times and getting a feel for the process