I recent backed a pie that included glucose and the recipe pretty much only said melt glucose...nothing about how to use it which lead me to much agony :)
So the question is ... is there a common ratio of glucose/water that you should use? I clearly failed in the beginning thinking that it should just be thrown into a pot and then heated...it sticks together into big blocks :S In the end I put in some water, but I assume that was a bit to late since it never dissolved 100%
If it's for a pie, by melt the recipe author probably meant to dissolve in the least amount of water. You can do that by making a glucose syrup, as Pulse mentioned. Place one cup of dextrose with a third of a cup of water in a pot and heat until dissolved. Commercial glucose syrups are typically 10 to 25% water.
If you melt solid glucose in a pan, which happens at about 146°C, it will burn.
Glucose syrup shouldn't need to be "melted" as it is an invert syrup (like corn syrup) and should not crystallize. It is however easier to pour and mix into items if it is warmed and I'm guessing that perhaps the recipe writer might have meant to warm rather than "melt" it.
Treat it the same as you would if you were melting honey that had crystallized: Remove the lid from the bottle and place in a small saucepan of gently simmering water until the glucose is warmed and easy to pour.
If you're baking a pie that requires glucose syrup, such as pecan pie, you could use corn syrup, which is a similar thing. It is possible to make your own glucose syrup, but the results can be suspect.
The alternative to glucose/corn syrup is a sugar syrup it is, however, quite different and is simply made by combining sugar and water in a heavy bottomed pan and gently stirring until the mixture begins to boil. It then needs to be cooked for several minutes until the temperature is approximately 120c.
