Live Beer-Long Life

Unfortunately, this blog does not reveal that living a life of beer is the secret to long life! However, for brewers who care deeply about quality, it will still be highly valuable when put into practice.

Live beer can be classified as beer packaged with living yeast & is familiar to most breweries and beer lovers who have enjoyed beer formats such as Cask Conditioned Ale in the UK or many of the wonderful Belgian beers refermented in bottle. Live beer is a wide classification however and unlike bottle conditioned beer where significant refermentation in package takes place this is not always the case in live beers.

Throughout most of history, most beer would have been “live beer” with living yeast present in the package. It is only relatively late in the journey of beer industrialisation that “brewery conditioned beer”, beer which is matured, clarified (often stabilised) and carbonated in the brewery became the status quo.

Brewery conditioned beer is a good fit for the most popular industrial beer styles as a bright and clear appearance can be presented and maintained throughout the shelf life & microbiological stabilisation such as “sterile filtration” and pasteurisation can be performed to secure quality objectives which are especially critical when working at large scale. Large breweries have also become highly advanced and skilled when it comes to technology and procedures required for strict oxygen control.

Although still a challenge, large breweries are well placed to make highly consistent brewery conditioned beers.

Smaller independent and craft breweries are not in the same position, and even when large investments are made in technology, expertise and laboratory equipment, it is difficult to compete at making brewery conditioned beer with excellent flavour stability. This challenge is exacerbated by the variety and complexity of the styles produced by many small and craft brewers, which is a welcome component to the industry but these beers, especially hop-forward styles can be more challenging than subtle lager beers.

Making “Live-beer” can significantly improve flavour stability!

For anybody lucky enough to attend Hop and Brew School Italy 2024 at Mr. Malt , Fermentis included a section demonstrating strong evidence to support sensory improvement of live-beer as beer ages.

A concern from some breweries around packing with yeast is a fear that fermentation byproducts will disrupt flavour, this is especially the case in hop-forward styles. In my experience these concerns can be mitigated with close control over residual sugars, priming and how much refermentation is allowed in the package, the flavour stability benefits from live beer can be achieved and fermentation byproducts do not have a detrimental impact when this refermentation is minimised. Due to yeast presence & natural metabolic pathways, issues with VDK off flavours are very unusual in live-beer. I was involved in a successful project to limit flavour deterioration in a bottled hop forward IPA, with these fundamentals being key to minimising flavour deterioration in 12-month-old, small pack beer.

Key Control Areas for live-beer

• Yeast count- Typical targets are 0.25-0.75million cells per ml but as little as 10,000 cells per ml have been described in MBAA literature as being enough to provide a positive impact.
• Yeast Type- Most yeast strains will perform the flavour stabilising function but selecting a strain with optimum flocculation, health, vitality and lack of contaminants is key. SafAle F-2 is a reliable strain optimised for the task.
• Residual Sugar- Simple attenuation limit tests are useful to confirm all fermentable sugars have been utilised. Be mindful of hop creep! See Appendix.1. (Attenuation) & 2 (VDK test-sensory)
• Priming Sugar- With careful matching of, temperature, pressure & CO2 in solution post fermentation priming may not be required. Where it is used low rates (e.g. 0.5-2 grams of sugar per litre of beer) can be used to provide minimum in pack refermentation, limiting fermentation byproducts.
• Hygiene- Packaging with yeast reinforces the nutrient-hurdle in beer as the controlled inoculation of yeast is effective in scavenging nutrients making significant contamination more challenging. Nevertheless, as with most brewing practices strict hygiene to prevent spoilage is critical & simple validation checks are useful, especially where pasteurisation and “Sterile” filtration are not in use.
• Clarity/Appearance- Clarity goals will vary depending on the beer style, especially regarding colour and hue. Some beers have an attractive appearance with significant haze levels but other do not. With optimised raw material selection, fining and stabilisation use, all appearance goals are still achievable in Live beer, but sediment will be a factor, and clear labelling is necessary to provide customer reassurance.

F2 Dosage guidelines

Try one beer and see the shelf-life improvement for yourself

Often laboratory equipment is expensive but one of the most critical pieces of equipment for this project is… a shelf!

Keeping a library of every batch packaged, tasting and recording at regular intervals is critical to making progress in shelf-life improvement projects. This library is also very useful should there be any complaints or queries about a batch from customers.

Live-beer should be a good fit for craft brewers seeking high quality beer throughout the entire shelf life of the beer. I am not alone in thinking this: Ken Grossman a founding father in American craft beer at Sierra Nevada brewing company may have scale and access to best equipment in the world now, but when he founded the brewery, he knew that live-beer was the best strategy to protect his beer in package.

From his book Beyond the Pale: “We had a good safeguard against oxygen with our bottle conditioning process. Any oxygen picked up in the process would do minimal, if any harm to the beer.”

Appendix 1. Attenuation limit test

This test can be employed to wort taken before fermentation.

• Fill a 750 ml sanitised flask with wort.
• “Overpitch” with a heaped teaspoon of the brewing yeast culture used.
• Add a cotton stopper and shake vigorously.
• Store at room temperature (~20 ͦC) and allow to ferment, measuring the gravity every 24 hours. Keep shaking intermittently or use a stirrer.
• When the gravity results stabilise for 48 hours the attenuation limit has been reached.
• The results can be used to modify the mashing regime to make the wort fermentable.

Appendix 2: Adapted, simple VDK test.

• Take 2 x 100 ml samples of beer from maturation.
• Cover both with foil or Petri-film.
• Leave one sample at room temperature.
• Heat the other sample to 65 ͦ C and hold for 20 minutes.
• Cool the sample back to 20 ͦ C.

Smell and taste both samples, the heating converts the precursors into the aromatic VDKs.

Continue maturation if levels are unacceptable in one or both.

When aromas are acceptable in both samples it is a good sign that progression is possible.

NB. Although a useful test to help monitor Diacetyl rests and maturation requirements, it is very dependent on the sensory skills of the individual or team. The most accurate test is performed by GC analysis and is therefore only available to breweries with the most sophisticated lab facilities or through outsourcing. Many brewers, especially in the US, are utilising the alpha-acetolactate-decarboxylase enzyme as a simple convenient control measure.