Why is high protein grains a problem in brewing beer?

Question

If you have some resources for me to study it would be great.

Answer 1

Mashing- a barley high in proteins are usually low in starches.

Proteins not reduced can cause haze.

A thick protein laden wort is more difficult to transfer as it may gum up pumps. Gums may also decrease yeast attenuation rates.

Proteins can have both positive and negative affects on a beers' head formation.

Answer 2

Excessive proteins can cause a beer to throw a haze, reduce mash efficiency, decrease a beers' stability, and increase total processing costs.

(I am learning to love the internet sources)

A very good article on proteins and beer.

http://www.expasy.org/spotlight/back_iss...

http://www.scientificsocieties.org/jib/p...

http://www.scientificsocieties.org/jib/p...

Concerns about protein haze.

http://www.brewrats.org/haze.html

http://www.regional.org.au/au/abts/1999/...

http://www.allaboutbeer.com/homebrew/pro...

A major concern is glucans and increase in proteins also brings about an increase of glucans. Beta-glucanase acts on gum-like materials in the malt to help improve lautering and beer clarity. A carbohydrate, beta-glucan is made up entirely of simple sugar molecules, just like starch. The critical difference between the two comes in the structure of the bonds between the individual sugar units.

The gum-like character of beta-glucan can increase viscosity of the wort during lautering and lead to slow run-offs. This will be especially true when grains high in beta-glucans such as wheat, rye and oats are used. Also, beta-glucans tend to be soluble in hot wort but insoluble in cold beer and thus may contribute to chill haze. If these problems are encountered (or anticipated) attention may be paid to increasing beta-glucanase activity in the mash.

Beta-glucanase is reported to work best at mash temperatures of 40 to 50 deg C or 104 to 122 deg F. The mid-point of 45 deg C or 113 deg F is often recommended for optimal beta-glucanase activity.

Foam Stabilizer

http://www.asbcnet.org/journal/abstracts...

http://www.accessmylibrary.com/coms2/sum...

Check it-Wiki

http://www.brewwiki.com/index.php/Head_R...

For Clarity

http://www.pqcorp.com/marketsserved/Brew...

Home Brew & Body

http://www.howtobrew.com/section4/chapte...

Answer 3

Proteins enhance the body of your beer, but can hurt clarity. Save high protein adjuncts like wheat, flaked barley and very dark malts for wheat and dark beers where clarity is not a significant consideration. If you are brewing a light beer where clarity matters, choose two row pale malt or pale malt extract base and add only enough high protein darker malts to achieve the desired color and body.

Answer 4

http://www.ars.usda.gov/is/AR/archive/se...

http://www.beer-brewing.com/apex/barley_...

The main problem with high protein barley is not the % protein but the type of proteins. The maltster and brewer want a barley with a degradable protein profile. Certain large molecular weight proteins interfere with foam formation and stability. If these proteins are not degraded by other proteins, called enzymes, they interfere with foam formation and retention. Also clarity is a problem if certain proteins are not removed in the brewing process. The great majority is removed during the boil hot break and during the cold break. Yet another consideration is the process type and time required treating the protein fraction of certain malts.

When the proteins in malt are of high molecular weight they effect a beers alcohol content, clarity, and astitics. To control these parameters the proteins are degraded in the mashing process. In older six-row varieties a long step mashing or decoction mashing process was required. These techniques are labor-some and expensive. Because of brewing economics many new lower protein varieties have and continue being developed. This has best been seen with the two-row varieties.

On practical level barley varieties are being developed that withstand high temperatures. Related to the processing of mashing, some enzymes are deactivated (denatured) by heat. If a variety can be developed with heat resistant enzymes a greater degree of conversion can be realized. This gives more fermentable sugars per bushel for the brewer. When a barley variety contains lower weight proteins coupled with heat resistant enzymes lower costs and greater profits can be obtained.