This slow-pour means the CO2 has nowhere to go - which leads to bloating when the liquid is disturbed in your stomach and the remaining carbon dioxide is released - especially once you add food to the mixture.
So before you try to send back a beer for having too much foam, remember that the foam is actually protecting you from feeling full and uncomfortable.
Join thought-provoking conversations, follow other Independent readers and see their replies. Want to bookmark your favourite articles and stories to read or reference later? Start your Independent Premium subscription today. By use of both barley and wheat in the grist, they ensured a good variety of high molecular weight protein and low molecular weight proteins to achieve a good stable foam. As always brewing liquor is of great importance to the quality of your product.
Having a handle on its composition and its treatment can really make a huge contribution to beer foam quality. Metal ions such as iron will have a very positive effect on the foam, lacing and head retention all enhanced through their ability to bind proteins and iso-alpha acids.
However, despite this very positive benefit, these ions can cause no end of further quality issues as well as being potentially toxic. For this reason, metal ions of greatest importance to the brewer are Calcium and Magnesium.
These bivalent ions will form the needed ionic bonds in hydrophobic areas encouraging cross linkage between iso alpha acids and proteins. These also have fewer negative impacts on flavour when present in the correct amounts. The influence of the constituents of brewing liquor on the pH throughout the process should always be given careful consideration in many aspects including beer foam.
The pH of the mash dictates protein extraction and enzyme activity and in the boil the pH of the subsequent wort will influence protein coagulation and denaturation.
Nitrogenous material in beer i. In foam positive proteins this causes the hydrophobic end to pick up a charge making it hydrophilic. This affects the entire balance of the system that leads to bubble formation so will cause the bubble structure to collapse.
This phenomenon explains why some sour beers appear to have poor foaming ability. Not only will this give a superbly bright beer but the addition of isinglass to beer will help bind up and drop out lipid materials for improved foam and flavour stability.
Getting the correct addition rates of kettle finings is also important, over boiling and over dosing of finings can overly reduce content of important proteins in foam formation. At first it sounds counter-intuitive that the use of Antifoam will help improve the quality of the foam but each time foam is formed, future foaming potential is lost. Avoiding boil overs or foam loss during fermentation means that important foam positive proteins often the first to form foams in processing will be lost from the beer over the side of the vessel.
The formation of foams is prevented, and excessive foam is knocked down with the introduction of highly hydrophobic silica which disrupts and prevents the foam formation. Use of antifoam also helps keep the brewery clean and can also allow the increase in capacity allowing vessels to be filled to a greater percentage of their overall capacity. When used at correct levels, it has been proven that particles of antifoam will attach to the yeast cell walls removing them from solution in the beer.
This means that the action of the antifoam is completely neutralised and removed with the yeast in normal processing. However, all the beneficial foam positive proteins remain unaffected and in solution in the beer ready to contribute to stable head formation.
Owing to their hydrophobicity of iso-alpha acids plays a great part in foam stability. It is thought that these compounds act by bridging the proteins producing addition support to foam structure this is why the area where the foam meets the beer often tastes most bitter.
Reduced hop extracts such as tetra hop can also help improve foam when added post fermentation because these are more hydrophobic so are more effective at supporting the foam structure. Yeast autolysis occurs when stressful conditions cause the membranes of vacuoles inside the yeast cell to start to break down. This in turn releases hydrolytic enzymes such as lipases and proteases into the cell which weaken the cell structure causing them to burst open.
As well as the potential to add off flavours, this process will also release foam harming proteases into beer. The strategy to avoid this issue is simple, reduce yeast stress throughout fermentation and reduction of yeast count in finished beer as quickly as possible. Pitching healthy yeast at the right levels with suitable oxygenation in a temperature-controlled environment free from contaminants to give a consistent fermentation is vital to reduce yeast stress.
Another important consideration is use of a good quality yeast nutrient such as Murphy Yeast Aid or Yeast vit. These contain a balanced blend of essential amino acids, zinc and other trace elements and vitamins to ensure that yeast has everything it needs to give a healthy stress-free fermentation.
An often over looked aspect of yeast flocculation is the role of calcium. Effective yeast cropping and use of finings post fermentation will also help reduce break up of yeast cells removing them before this happens. Rinse it in clean water. Let the glass air-dry upside down on a rack. Temperature is also important, as it may affect bubble size and uniformity, which feed back into the overall mouthfeel.
Temperature will vary based on beer style, but as a broad rule, ice cold and room temperature will offer you the ideal experience from a beer foam standpoint. Start gentle, with the classic degree angle, and pour down the side. As you reach the final quarter of the pour, pour hard, straight down the middle, to encourage nucleation.
The ratio of soft pour to hard pour will again vary with beer style. Hefeweizens and wits generally benefit from a more vigorous pour, while stouts should be poured more conservatively — often meaning filling the glass halfway so you can top the head off continuously. And of course, with nitros, you go hard from the start. There are times when you may not have everything you need for the perfect pour or times when drinking a beer straight out of the bottle just feels right.
Many beers are actually intended to be enjoyed from the can or bottle. So, per usual, let the circumstances dictate what constitutes your peak drinking experience. But if you really want to bring out the best in a beer, a good pour is crucial to showcase one of the most notable — and interesting — elements of it: beer foam!
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