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A Guide to Hard Seltzer Filtration and Stabilization

Last updated:6/2021

Applies to: producers looking to evaluate filtration equipment and media for use in hard seltzer. It outlines general steps of hard seltzer filtration and provides options for equipment/media that can complete each step.

Hard Seltzer Filtration Steps

Whether you’re thinking of adding a hard seltzer product to your lineup or have already shifted gears to facilitate production of this popular beverage, filtration and stabilization options should be carefully considered. As production volume, batch size and/or frequency increase, the filtration and stabilization method you use can have a significant effect on your efficiency and profitability.

While filtration setup will depend on the needs of each individual producer, all setups generally complete the following 4 steps:

  • Yeast & Solids Removal: Removes majority of yeast solids, reduces haze and cloudiness, improves product visually, mild sensory improvements.
  • Color & Aroma Removal: Produces a sensory neutral seltzer base.
  • Sterile Filtration: Reduces microbial load (removes yeast and bacteria).
  • Final Package Stability: Deactivates spoilage microorganisms including yeasts that can cause refermentation, and others that may produce unacceptable sensory attributes.

In this article we will discuss choices of equipment and media to complete these steps. For more detailed recommendations on order of operations and sample filtration layouts, please read our Hard Seltzer Best Practices Guide.

Filtration Types

The following filtration types can be used for the first three steps of hard seltzer filtration (yeast & solids removal, color & aroma removal, and sterile filtration). They cannot be used for final package stabilization.

LENTICULAR FILTRATION

There are many advantages to lenticular filtration and it is very scalable if you’re unsure how fast you may be expanding production. This is a very popular and cost-effective way to do the bulk of your depth filtration before and/or after sweetening and flavoring has been done. It uses nominally rated  filter media modules with a range of porosities and can be used at a variety of points in the filtration/stabilization process.

What steps can I use lenticular filtration for?

  • Yeast & solids removal: bright polish with 2.5 μ or K250 grade media (or tighter if turbidity allows).
  • Color & aroma removal: AKS4 carbon embedded media following the bright polish

SHEET FILTRATION

Sheet filters and media have been around for over a century and are popular with beverage producers of all types and sizes. Advantages include the ability to use a diversion kit to filter through two grades in one pass. This is a handy piece of equipment for smaller batches if you already have it. However, if you’re starting from scratch there are more efficient ways to save on product, media and labor, especially as batch sizes and frequency of filtration and packaging increase.

What steps can I use sheet filtration for?

  • Yeast & solids removal: bright polish with 2.5 μ or K250 grade media (or tighter if turbidity allows).
  • Color & aroma removal: AKS4 carbon embedded media following the bright polish

CROSSFLOW FILTRATION

Crossflow has the highest capital expense of all the filtration methods listed. However, for larger continuous batches of hard seltzer this becomes an excellent choice for full automation and 24-hour filter runs without constantly replacing media. Our VLS crossflow filters can be expanded with additional membrane banks as batch sizes increase. The VLS Unico model includes a sintered stainless-steel membrane that can filter liquids containing high solid content in one pass, producing a ready-to-package product. This allows for further savings on potential losses.

What steps can I use crossflow filtration for?

  • Yeast & solids removal

CARTRIDGE FILTRATION

Cartridge filtration is a common choice for carbon and sterile filtration steps. In regard to sterile filtration, cartridges are the only option for absolute media as the pore size can be guaranteed by means of integrity testing. Lenticular, sheet, and crossflow are all examples of nominal media where the pore size rating is an average, not a guarantee. It is a high precision filtration method that is a popular choice to use after a beverage has been sweetened, flavored, and filtered through a suitable depth filter such as lenticulars, sheets, or crossflow. It is also flexible in where it can fit in your setup, as its ability to withstand pressure is higher than other filtration types allowing it to be in-line with packaging.

What steps can I use cartridge filtration for?

Final Package Stabilization

It is important to note that sterile filtration does not lead to package stability due to possible equipment or package contaminations. Seltzer pH and alcohol levels are microbially more risky than those of other fermented beverages and for this reason it is highly recommended to complete a final package stabilization step.

Options for this in the past have included tunnel pasteurization as well as treatment with potassium sorbate. An increasingly popular method for this is Velcorin® treatment. Velcorin deactivates spoilage microorganisms including yeasts that can cause refermentation, and others that may produce unacceptable sensory attributes. Due to the unique physical properties of Velcorin, a Velcorin doser is required to atomize it into the product at the point of packaging.

Learn More

For more information about hard seltzer fermentation, see our article and downloadable guide "Best Practices for Hard Seltzer Fermentation" by clicking below.