I missed this post cause I joined the site recently but for future visitors to Spain I´d recomend not to bother too much looking for great local beers, simply there aren´t many.
In places like Madrid or Barcelona you may find the odd bar serving their own beers but this is the exception to the norm. Yet, a national beer that is worth trying is Voll Damm, a dark, strong double malt stuff which is quite tasty.
By and large, I find that in hot countries people tend to prefer light, fizzy, refreshing beers. Besides, the culture of drinking in Spain, for example, revolves around wine obviously.
There are also historical reasons that explain the little differences that exist between beers in Spain. During Franco´s dictartorship the price of beer was fixed by the authorities and all brewers had to stick to it. Therefore, everybody used more or less the same ingridients and techniques. That hasn´t change much I´m afraid.