Beer Head RetentionSaturday, December 19th, 2009
Beer head formation and retention can tell you more about your brewing process than you could have imagined, as you will soon see. Shortfalls in your brewing practices can be robbing you of that long lasting head that you are seeking on your favorite pint.
So, what makes beer foam?
LTP1 is a low molecular weight compound and is the primary substance in your beer needed for head formation. It has been shown that during the wort boil this compound is denatured and converted from an inactive form to a form that will actively make good foam in your beer.
Protein Z is an albumin, which means that it is soluble in water and coaguable by heat. This compound has a higher molecular weight than its partner, LTP1, and is the primary substance in your beer needed for head stabilization, or retention.
From what we have discussed, you may think that simply adding malts high in protein, such as wheat malt, are the answer to creating and retaining more foam. I have read this in the past, tried this, and have had no success, because it is almost certain that the malt bills that I used at the time were overflowing with enough proteins to create and retain beer foam. One thing that might help for certain recipes is adding 1/2 pound of flaked wheat to the mash (or steep for extract brewers). Extract brewers in general may struggle with head retention depending on the age and quality of their extract. This is one more reason for extract brewers to take the plunge into all grain brewing.
So, where is the foam?
ANSWER: Foam destroying compounds that exist in your beer, bottles, kegs or glasses are robbing you of the foam that you strive to create. This is where the lack of foam, or lack of foam stability, can indicate flaws in your brewing process. Here are some examples:
- High alcohols (fusel oils from high fermentation temperatures, under pitching)
- Low carbonation levels (bubbles drag these proteins to the surface, causing more bubbles, more foam)
- Shaking kegs during carbonation (causing your beer to foam can use up these foam producing compounds before the beer ever meets the glass)
- Fat (soap scum or other fats occupy space on the surface of the beer, reducing foam)
- Protease production from stressed yeast (under pitching or under aerated, high gravity fermentation)
Good brewing practices are essential for good foam formation and foam stability. Here are some things to keep in mind when exploring how to improve beer foam creation and stability:
- Fermentation temperature must be proper for strain used (Belgian and German strains can tolerate more heat typically, others not so much)
- Vigorous boils are necessary to denature LTP1, so that it becomes an active foam producer
- Use the proper yeast pitching rate for your volume, OG and beer style (lager vs. ale)
- Make sure you have proper carbonation levels
- Proper water chemistry – see the brewer’s friend water chemistry calculator
- Clean all glassware (carboys and glassware)
- Adequately aerate the wort prior to fermentation
- Avoid the use of chilies, cocoa or any other food that contains fats or oils
- Do not shake your kegs to speed carbonation
You can easily determine if your beer is lacking foam forming compounds (ProteinZ or LTP1) or if you have too many foam killers such as the ones listed above. Here is a simple test:
- First, shake the problematic beer you are about to test
- Pour the beer into tall, clear and CLEAN glass
- Observe the amount of foam
If the shaking and the pouring has created foam, then your beer most certainly has all of the protein Z and LTP1 needed to create beer foam. If this is the case, your brewing processes may require some refinement as stated in the factors above. Your beer probably has some foam killers lurking in it that will not allow for a long lasting head.
If, however, the shaking and pouring do NOT produce foam, you may wish to experiment with the addition of malts that are high in proteins, such as wheat malt. A lack of foam after shaking almost certainly points to a lack of foam producers.
There are numerous factors that come into play when discussing beer foam formation and stability. Many studies have been completed, many resources written, and this article is by no means a complete resource on how brewing processes and chemistry affect this facet of beer production. This is, however, a very eye opening look at how good brewing practices can affect the production and stability of that sometimes elusive foam! The importance of solid brewing practices cannot be overstated.
For more resources on beer foam and stability: