Mash alcohol percentage.

Some yeast produce more alcohol than others.
The difference as I understand it is the ability of
the yeast to survive in the alcohol.

Using mash of = ingredients

One yeast will yield 8%

While others are now up to 23%

Alcohol is the result of conversion of sugar by the yeast.
When the Yeast reaches a alcohol concentration that it
cannot survive in sugar conversion stops.

So if the mash is able to reach a 23% alcohol concentration
but the yeast dies at 8% doesn't that mean that there is still
enough sugar in the mash to reach 15% alcohol concentration
after the alcohol has been distilled out and if more yeast was added
to it?

Sorry if this is a stupid question I am still planning my first batch.
I am after fuel for the most part so taste don't matter.

 

I suppose you could distill off the fermented alcohol and add more yeast... but why are you making beer at that point? Why not just make shine?

 

ABV is going to be dependent on two basic factors. The amount of fermentable sugars in the solution (specific gravity) and the attenuation rate of the yeast(the percentage of that sugar the yeast will convert to alcohol) The specific gravity required to reach 23% would be huge. In the range of 35lb's of grain or 25lbs of DME to get a 1.200 specific gravity in a 5 gallon batch at 90% attenuation. There are yeasts available that are able to survive at higher ABV (turbo yeast/super high gravity) but they are mainly used for distillers, not brewers.
When you say your after fuel? Do you mean actual ethanol fuel? If so, you'll never achieve that through fermenting alone.
If you mean fuel as in high alcohol beverage....just go buy some cheap vodka, It'll be way cheaper.

 

It appears the OP wants to discuss the mechanics of distilling. That is not allowed here.