Given that you're new to this, you need to understand the old saying, "brewers make wort, yeast make beer."
Whatever yeast you use, you need to control fermentation temperatures as best as you can in order to allow the yeast to do their jobs well. Yeast give off heat during fermentation, so the temps inside the fermentation vessel (called the "fermentor") is often 5 or more degrees F above ambient air temps. What Jeffy means by a "clean" fermenation is that your chosen yeast strains are allowed to work at the desired temps and produce little or no additional flavors, such as esters (fruity flavors and aromas) or phenols (usually peppery, clove), or fusel alcohols (i.e., those other than ethanol).
Given that it is Summertime, it is doubtful that you have a fermentation area in your house that is at ideal temps (55F for lagers, 64F for most ales). Fermenting in the 70's or higher is a bad idea, especially for a Dunkel.
Sub-terrain basements might work if temps get into the 50's down there. Refrigerators are too cold unless you get a Ranco controller and hook your beer fridge up to that.