What is lab filtration paper?

Laboratories require specialized, high-quality filtration methods for a variety of scientific research and experimentation processes. Purity, reliability, and validity of filter materials are essential for accurate measurements and data collection.

Filtration is a physical mechanical process for separating solids from fluids by interposing a porous medium through the fluids ca pass but physical particles cannot. Both the surface and the matrix of the filter medium retain particles from the fluid. Laboratory filter paper is considered a depth filter: filter fibers are arranged randomly, so it is not possible to determine a fixed porosity for a specific filter paper grade. Nominal retention is used instead for classification.

Quality filtering papers remove impurities and particles from liquid fluids as well as retain impure substances within the matrix of filtration material. As particles are trapped by the filter, the filtration properties of the material become altered. Random positioning of fibers within the filter paper, creates a secondary layer of filtration – which is why it is not possible to establish the nominal porosity of filter papers. Filtration papers can be described as depth filters because the material has a capacity to filter and retain particles when processing large sample quantities.

Filter paper is available in several optional varieties for an broad range of laboratory applications. There are two fundamental types of filter paper: quantitative and qualitative.

What is the difference between quantitative filter paper and qualitative filter paper? 

Qualitative filter paper

Qualitative filter papers are used when substance separation is necessary to identify material content. Qualitative filter paper offers a range of retention and flow options for a wide variety of laboratory processes. Nominal retention ranges from 2 to 20 micrometers, and thicknesses between 150 and 320 micrometers are available from specialty paper manufacturers. Filtration rate of qualitative filter paper is based on retention and thickness specifications, and these factors are related to the speed of filtration processes. Qualitative filter papers are used for qualitative analytical techniques to separate and identify substances.

Quantitative filter paper

Quantitative filter papers, also known as hardened filter papers, are used for quantitative and gravimetric analyses using pressure or vacuum filtration methods, especially when remaining precipitate is to be analyzed – and when minimal ash content is required.

Specialty paper manufacturers use acid wash methods to reduce ash content while achieving a high level of purity. The amount of ash produced by quantitative filter papers after furnace disposal is 0.0009% or less. Ash weight is insignificant and does not impact analytical results.

In addition, quantitative filter papers have superior wet strength in order to endure both pressure filtration and vacuum filtration. Qualitative filter paper by contrast has comparatively low wet strength. However, moisture-strengthened qualitative filter paper is also available for pressure and vacuum filtration.

How is filter paper used in the beer brewing process?

Beer clarification and degassing

The degassing and clarification of wort and beer is an important analytical step in the beer brewing process.

Passing the beer wort through paper filtration clarifies and degasses the sample. Ahlstrom beer filter papers are available in a variety of sizes and folds.

Alcohol content testing

In addition to determining alcohol content for consumption, it is also important to understand alcohol content to monitor fermentation rates as well as demonstrate compliance with legal guidelines and alcohol taxes. Degassing and clarification of the wort are necessary prior to alcohol measurement. Tools to measure alcohol content include the spectroscope and chromatograph.

Wort sample preparation

Ahlstrom beer filter papers facilitate efficient degassing and clarification of brewing wort. Choose from higher rate of particulate removal but with slower filtration times – or a lower rate of particulate removal with a faster filtration time. Ahlstrom beer filter papers are available in a variety of sizes and folds.

Freshness testing

Although the antibacterial qualities of brewing hops inhibit the growth of most microorganisms, certain bacteria strains can impact the flavor and appearance of beer. Taking filter samples is a common method for determining bacterial levels throughout the brewing process. Ahlstrom offers a variety of filters beer brewing quality control.

Color determination

Product color is an important aspect of the brewing process. The removal of all particulates is a crucial sample preparation step prior to color analysis. The most common clarification method is to pass beer and wort samples though a filtration membrane.

Bitterness testing

Bitterness is an essential characteristic of beer flavor. Bitterness is typically measured throughout the brewing process to monitor hop levels in pursuit of the desired flavor profile. International Bitterness Units (IBU) measurement is determined by the concentration of acids in hops.

Carbohydrate testing

Carbohydrates and sugars are important ingredients in the brewing process. Yeast fermentation plays an essential role in the quality of the final product. Clarification, degassing, and filtering are important steps in the preparation of samples.

Nitrogen and protein testing

Nitrogen and protein are an integral parts of yeast metabolism, shelf life, texture, and froth. Specialty filter papers are required to ensure purity in test results.

Filter paper filtration

Ahlstrom-Munksjö filtration papers are ideal for filtering wort and beer samples for analytical purposes. Our beer brewing filters are manufactured to laboratory purity standards to ensure testing results are pure and reliable. Filter papers are available in a variety of sized and folds.

Sulfur content testing

Sulfur components often result from the beer brewing process. This can produce undesirable flavors in beer. Filtration is required to ensure accurate measurement of sulfur compounds.

Minerals and solids filtration

Water quality plays an important role in the brewing process. Dissolved solids can have a critical effect on the taste of beer. Ahlstrom-Munksjö offers a wide range of specialized filter papers for purification, testing, and monitoring wort and beer.