Brew with less water than instructions

[Scandixbrewer]

I have a kit can of liquid malt extract, Morgans Royal Oak Amber ale, it's 1.7 kg. The recipe says to add 1 kg of sugar or malt extract for a total volume of 23 liter. What would the consequences be if I skipped most of the sugar/extract-additions and used less water, say perhaps to a total of 15 liter?

 

[GilSwillBasementBrews]

It would increase the amount of sugar present in the liquid which would increase your Original Gravity ( OG ) thus providing you with a higher alcohol per volume. So you would basically wind up with a higher ABV Beer just at a lower volume.

it’s a ratio of gravity points per gallon.The higher volume has more liquid to dilute the sugar content. The lesser volume has a higher concentration of gravity points.
So more volume= lower ABV. Higher Volume = lower ABV

 

[bruce_the_loon]

The 1kg sugar additions normally recommend so-called brew enhancers which contain a mix of fermentable and unfermentable sugars. You get extra ABV for the same volume, but you also get more of a malt body to the final beer. Now I've only ever brewed two canned beers like this, so my experience is limited, but logic dictates the following.

Not adding the sugar additions will reduce overall ABV in the same 23 liters. Reducing the water volume will thus return the overall ABV towards, or even exceeding the ABV of the full recipe. What you get out will depend on the exact ratio between water volume and the tin and additional sugars. If you have a hydrometer and some patience, you can start at say 12 liters of water, mix very well and take a gravity reading to see how far off the kit's predicted original gravity (OG) you are and then add more water to try and match the kit value.

You might lose some body and mouthfeel without the brew enhancer, but it will still be beer and as drinkable as the full recipe would be.