coopers stout lit + 1kg Dark DME + 1kg Dextrose?

[StephenT4]

Hi there, hope you can maybe help. I plan on making a coffee, chocolate and chili stout using a coopers stout kit as the base. I'd also like to up the alcohol quite a bit - not in order to get pished, but I like a strong sipper, especially in a dark beer and lets face it, a chilli coffee choc stout isnt the 'go to' beer for a heavy session (i've a lager, a coopers pale ale, and a cooopers heritage lager made with heather, honey and oats for that!).

 

I have a few questions though. In order to up the alcohol would 1 can of the stout + 1kg of the dark DME + 1kg of sugar have any negative effects on the beer such as making it too sweet or too thin (or not dark)? Using coffee, dark choc and chilli, not to mention a higher ABV, I imagine would counter any cloying sweetness but I'd appreciate your input.

 

I've also heard of intentionally souring a Guiness (by leaving it out for a week or so) and adding it to the kit after boiling it. Does anyone have any experience in this?

 

Any input would be appreciated. I did notice that Coopers have a recipe on their site that calls for one can plus 1.5 kg of LME and 500 grams brewing sugar which equals the 2kg of fermentables i would add, just don't want any non-stoutish effects from all that dextrose.

Any thoughts would be hugely appreciated!

Thanks!

Steve

PS Should also add that I'm considering reducing the amount of beer made to around 18 litres - more headroom for a lively beer and more booze :)