Stewing vs mashing, different sugars?

Hello all

Are there different sugars made during stewing whole grains for a crystal malt vs mashing, at same temps? If so is it from limited water and free amino acids, etc in whole grains relative to mash?
I am reasking this question in this area because I would like to understand better the reasons for adding sugar to a recipe to dry out the beer, then adding crystal back in to get body back.

Why not just increase mash temps slightly and use more grain in the recipe?
If crystal adds in head retention and body, does increasing mash temp do the same?

Yes, and no. The sugars in crystal malt are caramelised to various degrees, and therefore they aren't fementable. The stewing is just the first phase of making "crystal" malt and it similar to mashing in that you activate the amylases to break starch into maltose and other more or less simple sugars. Then, when the malt is dried temps are raised and the sugars caramelise.

By the way, increasing mash temp should provide more body, but through different means - amylases break starch not into simple sugars, but dextrins (oligosaccharides) that are soluble, but unfernentable for brewing yeast.

So if whole malt is stewed but not roasted, the sugars are more fermentable than after it is roasted and carmelizes the sugars?

meadmazer said:

So if whole malt is stewed but not roasted, the sugars are more fermentable than after it is roasted and carmelizes the sugars?

Click to expand...

Yup, but they're fermentable to the same extent as in a regular mash. As caramelisation is a really, really complex process (chemically) it makes lots of compounds that aren't fermentable but adds to taste complexity and body of beer.

One more thing - caramelisation occurs when an already converted malt is dried/roasted. If you roast a malt that is not converted ("stewed") different reactions happen and the products of the reaction have a quite different flavour profile, yet fermentability ia also lowered.