This 2 µm, Medium Speed grade has finer particle retention than Grade 601 but with slightly lower filtration speed. Grade 642 also has higher absorption than Grade 601. It is used in general laboratory applications to retain particles above 2 µm in size. Grade 642 is also found in agricultural and environmental laboratories for plant growth trials, soil testing, and air analysis for monitoring specific contaminants and in the filtration of organic and sulfide precipitates.
Ahlstrom-Munksjö manufactures a full range of laboratory filter paper for use in the beer industry. Grade 642 is recommended for the WORT color test.
Ahlstrom-Munksjö 642 - 2 µm, Medium Speed.
Equivalent to Whatman Grade 2, 2 CHR, 20 CHR.
Please note the below grid is a recommendation of what diameter filter paper is compatible with glass or plastic filter funnels.
| Diameter of filter funnel (mm) | Diameter of filter paper required (mm) |
| 35 | 55 |
| 45 | 70 |
| 55 | 90 |
| 65 | 110 |
| 75 | 125 |
| 90 | 150 |
| 100 | 185 |
| 125 | 215 |
| 150 | 240 |
| 180 | 320 |
| 220 | 400 |
| 260 | 500 |
When folded into a cone (typically in quarters), it should fit inside the funnel with about 5–10 mm extending above the rim for easy handling.
What is filter paper used for?
Filter paper is used to separate solids from liquids or gases, acting as a semi-permeable barrier that allows certain substances to pass through while retaining others. It's commonly used in laboratories for various applications, including filtration, sample preparation, and analysis.