The most consumed beers in the world are lagers. Lager is German for “storage” as this beer style was originally stored for extended periods before drinking in cool caves where they were also fermented.  Lager yeast strains were some of the first yeast strains to be isolated in the purest form without contaminations. These beers have been considered to have much longer shelf lives than ales. This particular yeast strain likes to ferment in cold temperatures and requires extended maturation periods than its ale counterparts. Lagers require special care and attention in the production process that the MARKS horizontal lager tank addresses. 

Lagers involve additional considerations when fermenting and are a much more fragile style to brew vs ales. Lager beers are made with a bottom-fermenting yeast that requires cooler temperatures than ales. Horizontal lagers lower the height-to-volume ratio. Lowering the hydrostatic pressure on the yeast greatly decreases the chance of autolysis of the yeast (rupturing of the yeast cell) – this greatly reduces the risk of off flavors. Horizontal lager tanks give brewers the best chance to create a crisp clean beer true to style. The tank geometry also provides faster clarification times once conditioning is complete. It is also very common to naturally carbonate in horizontal lagers during this maturation period.  

“Spunding” translates from German to “bunging.” This method of natural carbonation involves monitoring current gravity in your fermentation and sealing off the tank after the initial kick-off of primary fermentation subsides. Capping the tank builds pressure within the vessel and carbonates the beer. This method of carbonation differs from America’s more common “forced carbonation” practice. However, the proven German practice of spunding is one approach to creating tiny bubbles and a creamy mouthfeel in beers that is simply not achievable through forced carbonation. This natural process brings with it several other benefits worth considering as well.  

Spunding can not only increase production speed through faster fermentations, attain a beautiful mouthfeel in your beer, reduce off flavors and can lower your spending on CO2 from eliminating the need to force carbonate post fermentation. It’s also the only way to brew if you want to uphold the 1516 Bavarian Law of Reinheitsgebot!  

Tightening US CO2 shortages are continuing to hit small businesses and breweries all across the country with strains expected to continue in the coming months which makes spunding your tanks that much more important to save on costs and lower your carbon footprint.  

More importantly spunding can create many benefits to your fermentations. Pressure can suppress the expression of volatile compounds that form esters. A pressurized fermentation can suppress these unwanted esters from many yeast strains. This technique can create very clean lager-like ales in less time. Spunding your tank can also increase hop aroma and flavor by reducing the loss of volatile hop oils that typically escape with C02 blow off during fermentations. As we know, the role of American brewer’s is to maximize that hop character! Dry hopping under pressure has it’s own unique challenges but MARKS has an equipment solution for that. Infusion Vessel , Hop Doser

Spunding under pressure beyond adding the spunding valve to your tank requires some other safety considerations. The most effective and safest way to spund your tank is utilizing an ASME- pressure rated tank when the working pressures exceeds 15 psi. While Ale yeast strains fermentation threshold is in the 8-12PSI range, lager yeasts are more often in the 15-20PSI range necessitating the need for an ASME pressure tank. With the continued dominance of Pilsners and other German Lagers in American beer production, an ASME pressure vessel gives you superior capabilities in natural carbonation when brewing certain styles of beer and gives you the capability to brewing beers true to style.  

When using a non-ASME rated tank for processes that require greater than 15 psi, risks include higher weld stress and potential premature weld failures. This is why MARKS ASME tanks are worth considering.