How to Filter Sap
February 20, 2019
If you've ever seen sediment, cloudiness, or even chunks of sugar in your pure maple syrup, you know what sugar sand (aka niter) is! This is a perfectly edible (and natural) component of syrup but it can easily be removed with filtering. Most sugarmakers filter sap and syrup three times and this article and video describes that quick and easy process. Be sure to use professional filters designed for syrup making (not coffee filters, cheesecloth, or dish towels).
Filters are inexpensive and reusable so it’s a one-time purchase as you get started. We use one-quart filters which are a more manageable size for the home sugarmaker. They fit perfectly into a standard sieve stand and have small slits in each side so you can thread a dowel through and easily balance on the sieve stand so you have both hands free for pouring hot syrup.
Filters are included with many of our kits but you can also buy them separately here.
Note: If you're making black walnut syrup, don’t use the Orlon or a similarly thick filter. Walnut sap contains more pectin than maple sap so it’s too thick to run through this type of filter. Try cheesecloth or a thin strip of clean muslin.
This short video shows the entire process:
Filter #1: This step is done each day as you collect sap to remove debris that may have fallen into your sap bucket (one more reason to use a closed lid system!). Suspend the thinner prefilter over a clean bucket and slowly pour the sap through to seine out debris. When done, rinse this filter with plain hot water, air dry, and save for later. Refrigerate or freeze the sap until ready to boil.
Filter #2: This step occurs midway in the boiling process as sap reaches a temperature in the 215°F range. At this point, concentrated sap is moved from the larger pan or evaporator and poured through a thin prefilter into the finishing pot. This removes the majority of sugar sand which can make syrup cloudy.
Filter #3: The third and final filter is done after the sap has reached its finished temperature and is poured into bottles. For this filtering, put the thinner prefilter inside the thicker Orlon filter. Slowly pour the finished sap through these filters and into clean, hot bottles or jars. Syrup is now done!
Cleaning Filters. As mentioned earlier, these filters are reusable and should last for years if cared for properly. Never wash with detergent or dish soap as this can affect the flavor of finished syrup. After use, simply rinse well in hot water and hang to dry. Do not wring or twist the filters as this can tear them or alter their shape.
If you’d like to learn more about entire boiling process, click over to this helpful article, “How to Make Maple Syrup.”