I recently dug this one up… It produces glucose in the wort. I have no idea how it will taste, but that technique has been demonstrated at the Research Brewery in Weihenstephan, Bavaria.
Maltase is the enzyme that converts Maltose into Glucose. Its optimal temperature range is 35-40C. During a normal mash schedule, no Maltose is present when the Maltase is active in its optimal temperature range and before. Once starch is being converted into Maltose, the temperatures are too high for Maltase and by that point it already has denatured. Therefore, no Glucose is made during conventional mashing schedules.
This schedule therefore uses a partial portion of the mash to use for this preliminary Maltose conversion at 64C (3:1 water to grist ratio) for about 40 minutes. Like in the main mash, care is taken that the pH is at 5.6, adding acidulated malt as necessary.
Once the Maltose is converted, the rest of the strike water is added to drop the temperature in the Maltase range by adding the rest of the strike water and now the rest of the grain is added to the tun. This brings the temperature of the mash back down to 35C and a normal mash schedule is run, after a Maltase rest at 35C for 10 minutes is used in order to convert any Maltose to Glucose.
Then the mash proceeds as normal. Clever indeed! I’ll post the result later.