Ok,I've worked with the Cooper's kits (I use the term loosely). The "09810" isn't the number code of the yeast,it's a Julian date-98th day of 2010. Just thought you'd like to know. The light dry malt (in other words,plain light DME),does cake up. Just keep stirring,it'll dissolve. You can use it in a boil. But this kit has NO bittering hop separately done.
The dextrose is intended to dry it out a little,not just more ABV. But it should boost the hops a little.? I've found the Yeast works a lot better in a small starter,or at least re-hydrated. Starts a lot faster & cleaner. Let's see..what else?
And watch those primary temps! Cooper's stuff can come out very clean if you do that while being patient & let the yeast have all the time it needs to reach FG & clean up. Let it age in the bottles for at least 3-4 weeks,then 5 days in the fridge. And prime correctly as well. I just don't get any of these cidery,sour,etc flavors everyone blames on all extract kits. Especially Cooper's. Extract brewing is easier in one respect to get started. But require a lot of attention to all the little details to get it too come out good.
Just like any other system of brewing. So if yours doesn't taste right,blame the brewer-not the brew. Kinda the same as we used to say,"hate the game.not the player".