Enhancing Beer Head Retention for Home Brewers

by Brad Smith on June 25, 2008 · 12 comments

Stout Beer

An important characteristic in homebrewed beers is the ability of the beer to retain a nice foamy head for a long period of time. Commercial brewers go to great lengths to improve head retention by a variety of additives. However homebrewers also have access to ingredients and additives that can help your foam last until the last drop.

Note that enhancing head retention is closely related to enhancing the body of the beer. Foam is the result of CO2 bubbles rising through the beer. These bubbles attach themselves to substances in the beer and form a skin around the bubble. Obviously the more CO2, the more bubbles, but the goal of the brewer is not bubbles but stability of the head. As foam collapeses, evaporating bubbles tend to solidify the beer near the surface, allowing more beer to be poured with less foaming after a few minutes have passed.

Head stability depends on the presence of substances with low surface tension in the beer which can form stable elastic bubbles. The two primary contributors to head retention are certain high molecular weight proteins and isohumulones (alpha acids from hops). Therefore beers with more proteins that are highly hopped will have higher head retention.

Methods for Improving Head Retention

We will explore the following possibilities:

  • The use of body and head enhancing malts such as crystal, wheat, or carafoam
  • The altering of the mash schedule to enhance head retaining proteins
  • The use of heading agents – additives that enhance head retention
  • Addition of high alpha hops – which will increase bitterness, but also increas isohumulones that enhance head retention
  • Limiting the use of household soaps on drinking glasses and homebrew equipment
  • The use of a nitrogen and CO2 mix for carbonation and serving
  • The shape of the glass used to serve the beer

Head Enhancing Malts

The inclusion of proteins and dextrines enhance the body and head retention of finished beer. Unfortunately when used to excess, proteins and dextrines can interact with tannins and reduce clarity and promote cloudiness, so a proper balance must be struck. Crystal malts to include the light Carapils and Carafoam, and caramel malts.

These are the most common body and foam enhancing additives that enhance head retention primarily by adding dextrines and other complex proteins. The overuse of such malts can result in proteins reacting with tannins to create a chill haze. Similarly, other grains high in protein such as flaked barley and wheat can be used to enhance head retention, though again at the cost of clarity.

Mashing Schedule

Since head retention depends on the level of high molecular weight proteins, any step in the mash that breaks down proteins is undesirable. For example, a protein rest in the 50-60 C (122-140 F) range would not be desirable. To improve head retention you would generally favor a full bodied, higher temperature mash, with main conversion in the 158 F (70 C) range, and avoid intermediate protein rests.

Heading Agents

Homebrew shops sell a variety of additives, usually under the generic title heading agent. Some are intended to be added at bottling time, while others need to be added at the end of the boil. Follow the instructions included with the agent to determine what is required. Many heading agents are derived from an enzyme called pepsin that is derived from pork.

Other popular heading agents include iron salts, gums, and alginates. All heading agents will alter the flavor of the beer, in general making the character softer. In general, heading agents are not necessary for homebrews that are made from 100% malted barley and wheat. Heading agents are more commonly used in commercial beers that have high rice and corn content, lacking the necessary proteins of an all-malt beer.

Hops

As mentioned in the introduction, isohumulones which are a form of alpha acid also will enhance the head retention of beer. Alpha acid is the primary bittering agent in hops. Therefore highly hopped beers will have better head retention. Obviously overall malt-bitterness balance is still required, but one can use higher levels of hops, particularly in darker full bodied beers to enhance head retention.

Limit the Use of Household Soaps

Household soaps such as common dish soap and dishwashing soap have a significant detrimental effect on head retention in beer. You should not use household soaps on either your brewing equipment or your main bar drinkware. Detergent washed glasses in particular will quickly reduce the head on even a well constructed beer. Instead use a beer-friendly cleaning agent from your local homebrew supplier.

A Nitrogen Mix

Some beers, most notably Guiness Irish Stout, are carbonated and poured with a mix of nitrogen and carbon dioxide. CO2 is relatively soluable in beer, and therefore does not promote the formation of gas bubbles as well as non-soluable gasses. Nitrogen dissolves less easily in beer, and provides a better base for forming a stable head. However, nitrogen alters the perceived character of the beer, and use of pure nitrogen would result in an unacceptable mouthfeel and carbonation.

A mix, therefore, is always used. The mix varies depending on the style of beer – a low carbonation stout might be served with a mix of 25% carbon dioxide and 75% nitrogen, while ales and lagers might include more CO2 – perhaps 60% CO2 and 40% nitrogen. Low carbon dioxide mixes (25/75) can be applied by mixing the gases in the cylinder, but higher mixes generally require two separate tanks – one of CO2 and one of nitrogen. A high precision blending device either at the tap (i.e. a stout tap) or inline are needed to blend the two gasses for dispensing.

Shape of Serving Glass

The shape of the glass is also a determining factor in both head formation and head retention. A tall narrow glass enhances the formation and retention of the head, while short wide glasses do not. This is the reason many Bavarian wheat beers and Pilsners are served in tall narrow glasses. Use the proper glass for the style of beer you are pouring to enhance the overall presentation.

I hope you enjoyed today’s tips on improving head retention. Thank you for joining us on the BeerSmith Home Brewing Blog. Please be sure to subscribe for weekly delivery of the latest articles.

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{ 8 comments… read them below or add one }

bigmny4you July 2, 2008 at 4:59 pm

Excellent article on head retention. I especially liked the tips on detergent use. Thanx I didn’t know that.

crush July 26, 2011 at 8:07 pm

Some good advice! I’ve just brewed after a 2 year pause and my first batch had no head at all. I’m still not sure what the cause is, but after reading this article. I think possibly too low mash temp, since it’s new brewing equipment. Although the beer finished sligthly high…1.012.

Brad Smith July 30, 2011 at 12:24 pm

Hi,
I doubt that the mash temperature would have enough effect to create a flat beer. I would look to make sure you used a viable carbonating sugar and also that your yeast was still viable when you carbonated.

Brad

chris aylmer December 11, 2011 at 4:44 pm

HOW TO KEEP A GOOD HEAD ON YOUR BEER!
I have disc0vered a great way to give your beer a lasting head once poured into the glass and I haven’t seen it mentioned before on this or similar sites.
I brew bottled stout from pale malt, roast barley, flaked barley and hops. My beer is bottle conditioned and forms a really good head initially, but it tends to disappear halfway down the glass and the flavour does not seem so smooth without the head.
I had the theory that some powder or granules might help to give the bubbles something to cling to and help them come out of solution. First I tried adding a little granulated sugar on the tip of a teaspoon and immediately plenty of bubbles formed and the head lasted better than without this addition. However, I don’t like adding sugar to anything including my beer and in any case the sugar dissolves in the beer so that it would begin to lose its effect soon after addition.
So I tried adding a little sweet spice powder, maybe an eighth of a teaspoon. This did the trick beautifully and the head lasted all the way down the glass. The flavour was fabulous with the hint of spice and also the beer was very smooth on the palate. The spice powder is insoluble and so does not lose its effect.
I recommend trying this! Another thing to try is real ground filter coffee which is also insoluble and gives a great flavour too. I’m sure you could find other insoluble powders that do not affect the flavour of the beer if you prefer.

Ed February 14, 2013 at 12:08 am

I had trouble keeping the head on my home brew so I put a few scratches on the bottom of the glass with the Dremel and Ive had no trouble since. The brew retains its head right to the last drop.

Troy June 24, 2014 at 8:51 pm

I had this problem too – head retention dwindled within a few minutes after getting half way through my glass.

I took a very scientific approach: research, measurements, did it all.

FINALLY I got the perfect solution.

Drink the last half more quickly :)

Cheers
-T

chris aylmer June 27, 2014 at 4:41 pm

Thank you Ed! Brilliant! The idea of scratching the glass is absolutely spot on and worth all the myriad of ideas rolled into one and put forward on this site. I used my tile scribe to scratch the bottom of my beer glass and the head is now perfect and lasts down the glass, even at cellar temperature(rather than straight from the fridge), which is how I like my homebrew beer. I guess a lot of the glasses in pubs have been washed over and over and have scratches on them already.

chris aylmer July 16, 2014 at 6:09 pm

The scratching of the glass works to an extent, but for some reason tends to wear off after a few times. The glass probably needs to be completely DRY to get the desired effect. This is not possible if you want a second bottle of beer. I have read that a wet glass can cover up the scratches on the surface of the glass. I continue to find that adding a little mixed spice powder on the end of a teaspoon(before pouring the beer) has the most reliable effect. The flavour is enhanced and the head consistently lasts all the way down the glass.

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