If you're brewing with kits, and want a stronger beer, then brew higher gravity kits.
Trying to make a highly alcoholic beer from a kit simply by dumping a bunch of sugar, is going to produce nothing more than cidery rocket fuel. It might get you ****ed up ass over tea kettle, but it will more than likely leave you with a nasty headache as well.
If you want a strong beer, don't choose a normal gravity beer and decide that since you read about boosting gravity by adding more sugars to just add more sugar, choose a beet of the grav you want, just like if you wand a peach beer, don't choose a non fruit beer recipe and try to "figure out" how to add the fruit...get a kit or recipe that has everything you need in the right quantities you need. Recipes are about a BALANCE between flavors, bitterness, aromas, what have you, and until you get a few batches under your belt, and learn the fundamentals, stick with the already proven and balanced recipes. That way you don't have the extra step of trying to figure out what went wrong if the beer doesn't taste good.....if the recipe or kit already tastes good (and they would have gone through tastes tests and ALREADY before you got to them- you know they are already good, if not award winning beers, if you went with a kit or book recipe, they have been vetted) if there is something not right, you will have an easier time trying to figure out what went wrong in terms of your brewing PROCESS, not because you went off the ranch and on top of trying to actually learn to brew, you also through a bunch of crap into the equation.
Beer recipes are a balance...and if you add to one variable, that will affect other parts of it...For example if you decide to raise the gravity of a balanced beer...a beer where the hops balance out the sweetness...and you raise the maltniness of it without also balancing the hops, then your beer may end up being way too cloyingly sweet. Or if you just add sugar willy nilly it could become overly dry, or cidery.
At this stage most folks trying to do it don't know enough yet, and they won't learn just by jacking a recipe o your first time out of the box. Don't start altering recipes on your first batch, or else you're gonna be posting a thread titled, "Why does my beer taste like I licked Satan's Anus after he ate a dozen coneys?" And we're not going to be able to answer you, because you've screwed with the recipe as well as maybe made a few noob brewer mistakes that typically get made, and neither you, nor us, are going to be able to figure out what went wrong. Because there's too many variables.
Just brew a couple batches and learn from them, and read books about recipe creation before you start messing around. It's not about tossing stuff into a fermenter and seeing how it turns out.
Besides getting trashed isn't most of our goals, it's about making great tasting beers. Regardless of the gravity.
Yes I have a 14.5% abv barleywine that I brewed that has a 150 ibu bitterness and was made with 50 year old honey. But I didn't just dump a bunch of sugar into to get to some gravity. It was a special recipe that took a lot of work, and some brewing tricks like decoction mashing to do it.
It's got a nice balance to it, BUT it will take another 4 years til it's going to get drunk (I brewed it for my 50th birthday)
A lot of new brewers who come on here thinks it's all about making big beer.
But most of them don't know how to do it....
If you want to make strong beers, learn to make GOOD beers first.
Read and learn about creating great RECIPES, not just how to boost the alcohol content of a beer. Learn about the ingredients, how they affect each other, how they balance each other.
Don't just make it about high alcohol, make it about good beer, that just happens to be higher in ABV if that's what you want.
