What impact does excessively high diastatic power in malted barley have on wort fermentability?

Excessively high diastatic power in malted barley leads to the overproduction of simple sugars, specifically an excess of glucose, in the wort. Diastatic power is the ability of malt to convert starches into fermentable sugars during the mashing process. While fermentable sugars are necessary for alcohol production during fermentation, an overabundance of highly fermentable sugars like glucose can result in a wort with low residual sugar content after fermentation. This means the yeast consume almost all available sugars. The resulting spirit, after distillation, will have a thinner mouthfeel and potentially lack the desired complexity because the non-fermentable sugars and other compounds, that contribute to body and flavor, are minimized. An example is comparing a spirit made from a wort where a substantial portion of complex carbohydrates and dextrins remain unfermented – it will have a fuller body. Over-attenuation due to excessive diastatic power therefore diminishes the potential for creating spirits with rich and balanced profiles. Furthermore, a wort overly rich in simple sugars is more susceptible to bacterial infections, leading to off-flavors during fermentation. The yeast might also undergo stress from the rapid consumption of readily available sugars, potentially producing undesirable byproducts, thereby negatively affecting the distillate's quality. A distiller must balance the diastatic power of the malt to achieve the desired sugar profile in the wort, aiming for a mix of fermentable and non-fermentable sugars to optimize both alcohol production and the development of complex flavors and mouthfeel in the final spirit.