stopping fermentation and gassification.

[Dadux]

No problem about the "hijacking" ahaha you guys kinda solved my doubts anyway, and its interesting to read you both.
The truth is i have never personally carbonated the mead and i dont know how much CO2 its produced per sugar unit fermented, so i guess calculating the preassure a bottle can withstand would be hard. Still, it seems like something worth trying, but now that im aware of the risks, i'll be a ton more careful.

Also, Im kinda sure you knew at least part of this stuff but in case you didnt, there it goes:

About the taste of raw honey from backsweetening that is easy. Since honey comes from plants, i can tell you those produces mostly sucrose, then fructose and glucose. Most non-specialized living microorganisms have a regulatory sistems that allows them to just eat the less complex sugars first (they detect and consume them until the cost of absorbing something that is in too low quantity is greater that the cost of actually using energy to separate other more complex sugars into fructose and glucose). so, that means that yes, if you dont add extra raw honey the first thing thst is gonna run out is glucose then fructose then sucrose, then more complex molecules, that also exist in honey such as large polisacharids. this is most likely the reason why the taste is differentif you backsweeten, and also makes sense with what Mazer828 says. Also, the interaction between raw honey and the remains of the fermented honey may vary and change the taste.
Also about what Stasis said, you can taste all kinds of sugars, but they taste slightly different and actually the sweetness is different between different sugars. a 1.010 mead without backsweeten will, most likely, taste a bit less sweet than a 1.010 mead after backsweetening.

 

[Stasis]

About taste:
The taste of sugar in wine is a bit fake. When a wine is backsweetened with sucrose the bottle must be aged. After aging the sucrose is broken down into fructose chemically and tastes better. Sucrose is a disaccharid and fructose is a monosaccharid. Sugar is more complex.
Meanwhile, backsweetening with honey which contains mainly glucose and fructose (both monosaccharids) tastes weird.
This is why taste is a bad way to judge complexity: both complex and simple sugars can taste weird when used for backsweetening.

In honey the majority of sugars are glucose and fructose, both of which are monosaccharids and therefore more simple than sugar. This is the opposite of what mazer theorizes. There are also more complex sugars: sucrose (same as sugar) maltose and 'others' https://en.wikipedia.org/wiki/Honey#Nutritional_and_sugar_profile
Assuming that yeast don't eat the maltose under stressed conditions even though it is a disaccharid like sucrose, and that those 'higher sugars' are also not eaten, we have 8.6% of honey's sugar which are too complex.
To reach 14% abv we need 15lbs of honey. 8.6% of 15lbs is 1.3lbs - this is the amount of maltose and higher sugars in your must. 1.3lbs of honey raises your sg to 1.008.
BUT after a healthy ferment abv can go below 1.000 which means that your complex sugars can probably buffer your sweetness to even less than 0.008 under best case scenario...
Also, the ratio of sugars changes from honey to honey. Sometimes the complex sugars can be more than 8.6%, other times it can be less. This means that calculating or relying on complex sugars to be left behind is dangerous.
If this theory is correct you can only have a stalled ferment at 14% with FG 0.008. Any higher and you risk bombs. This is best case scenario.
I don't think yeast find it all that hard to eat maltose, and even then I wonder if it degrades into glucose like sucrose does by time. Even if it is hard to eat, I wonder if yeast would totally ignore maltose throughout fermentation. If yeast snack on maltose from time to time we are left with only 1.5% of sugars which are very complex and *maybe* remain until the end.

Anyway, yeast often restart a mead ferment which had stuck. There's nothing to argue here. Maybe there is slight oxygenation during bottling, a change in temperature, who knows. Yeast can restart a ferment and eat more than cane sugar, it has happened. Maybe Mazer828 is doing something very specific which creates little risk of bottle bombs, but I don't think it's as easy as using sugar to prime

 

[Dadux]

I see what you mean Stasis but i think the question isnt that, or at least that only. the problem would be what happens with yeast when you reach a certain ABV. Lets say i have a yeast that stops fermenting at... 14% ABV.
What does that mean? it means when my ABV is 14, it just dies of toxicity? does it stop fermentation and goes dormant? because, if the second is what actually happens, then what mazer says is totally possible. but if the yeast dies, then obviously is not. I am inclined to believe its the second, because if Mazer says he has done actually that, well, the yeast was obviously alive. Also, i must say that if you add suggars and the mead gets oxigenated a bit, the ABV would slightly go down, so it is possible that the yeast reactivates, fermentates a bit, then goes dormant again. Something simmilar has actually happened to me, when i racked last batch, fermentation restarted for a couple of days.

 

[Stasis]

A sweet mead is one that has leftover sugars from honey in it
What mazer is saying is that maybe when yeast go dormant they wake up and ONLY eat the sugar you primed the bottle with because sugar is simple. They leave the sugars from the honey alone because they are complex.
What I am saying is that sugar is actually probably more complex than the sugars left by the honey. If yeast are going to wake up they can eat all the sugars.
It is important to determine EXACTLT how much sugar is eaten because if too much is eaten, too much CO2 is produced and you get an over-pressurized bottle. A bottle bomb.
Mazers do report from time to time that their mead restarts seemingly 'spontaneously', which means they have no problem waking back up and continueing to eat the leftover sugars from honey. Also, there is no saying when a ferment will stall, which means there is no saying what leftover sugars you will have. Even if complex sugars are left exclusively until last, if you finish with a sweet mead it must be low sweetness. Anything above Fg 1.008 in this case would be risky. This 1.008 Fg is totally fictional, made up to show what the best case scenario is. I think the best case scenario never happens though.

What I think might be happening:
Yeast when waking up typically have one factor which has improved their living conditions slightly. This single variable typically improves their conditions just enough to consume just enough sugar to gassify the mead and avoid bottle bombs.
OR
Mazer is bottling mead which hasn't totally degassed. He is not introducing new yeast which minimizes chances of restarted ferments. He is also bottling quite soon after fermentation has stopped. Degassing could happen for a long time after ferment has finished unless a mazer speeds up the process. In normal wine bottles maybe that extra pressure normally breathes out of the cork by time, but when mazer seals the bottle with a crown cap or plastic champagne top the gas from degassing is not released. But I can't see how a non-degassed mead could ever be sparkling. Best I had was slightly effervescent but undetectable bubbles

These are all just theories. The important bit is
BOTTLING A SWEET MEAD WITHOUT STABILIZING IS POTENTIALLY DANGEROUS