Melanoidins

Ok, so my understanding of melanoidins is that they are formed during the boil. They are large polymers which have similar properties to the browning of meat from heat. (maillaird reaction, don't know about that spelling) My question is, are these fermentable? I would lean to say no because of many reasons. Also, do these form from pre-existing fermentable sugars? ie..Do you lose fermentability/fermentable sugars by boiling longer to gain melanoidins? Bassically what I want to know is when using melanoidin malts (vienna, munich ect..) do they deture the fermentability of the wort or do they have nothing to do with the fermentable sugars? Thank you to all who read this.:rockin:

As far as i understand it, a maillard reaction causes unfermentable molecules including melanoidins to form. They DONT ferment, As far as to deter fermentation, its more that they are just none fermentable and add mouthfeel and color. The more there are, the higher the final gravity

The higher a grain is kilned or roasted, the less fermentable it becomes. This is why the shift to the use of pale base from brown malt and other traditional malts during the industrial revolution. The extraction is greater. Pale 2-row and pilsner in general have a higher fermentablilty than pale ale malt, which is higher than Vienna, which is higher than Munich, which is higher than Brown malt etc.

Melanoidins are a browning reaction that takes place with carbohydrates and proteins under heat, moisture and oxygen. The longer you boil, the more melanoidins you will get, and the more fermentable sugars will be chemically changed rendering them unfermentable.

This does not stop when you kill the heat. Melanoidin reactions can keep going at room temperature. Liquid malt extract will continue to get darker even in a closed container at room temperature. The high concentration of sugars with the proteins continues to make browning occour. This is why old extract can look dark, much darker than the package says it should.

cool, kind of what I thought, thanks again!

Interesting history lesson from Beersmith.

Melanoidins are indeed part of the maillard (french word) reaction. They aren't only formed during kilning and the boil. They are formed in nearly every step of the brewing process including kilning and drying (malting process), decoction style mashing, and the boil (extended boil, roaring boil with high evaporation rate).

The difference between melananoidins and carmelization is that melanoidins are a result of a sugar to amino acid reaction, where carmelization is a sugar to sugar reaction.

Homebrew God John Palmer says that different flavor profiles can result from the different ratios of temperature and moisture content, meaning the melanoidins produced in the malting process could be slightly different than those produced during the boil. This is why the addition of melanoidin malt isn't always the best option for re-creating melanoidin rich commercial beers.

Brewsmith was also correct that melanoidins are unfermentable.

I wrote a short article on Melanoidins and how they relate to beer over at the Home Brewer's Haven if anyone is interested. All sources are cited from legit sources. Brew Strong also has a good audio radio/podcast which dives into melanoidins pretty in-depth.