One of the factors that we thought could contribute to filtration was the level of agitation. To test this, we did a test batch without any stirring at all and another batch where we stirred it 4 times during the brewing process.
TDS - One of the ways to determine extraction/filtration is to measure the Total Dissolved Solids. Typical ranges of TDS for cold brew concentrates are between 3.00% to 3.50% (also referred to as a TDS of 300 to 350).
- No Stirring - 325
- Stirring 4X - 346
Sediment - One of the defining characteristics of cold brew is the body, and sediment plays a big role in that. Every batch we’ve ever made has had sediment in it, but to varying degrees. While not a perfect test, we tipped the glass jars to see how much sediment had collected after 24 hours.
- No Stirring - Light Sediment
- Stirring 4X - Very Heavy Sediment
Conclusion - From our preliminary tests, level of agitation has an enormous effect on level of filtration. For people who found too much sediment and body in their cold brew, we recommend reducing the level of agitation. For people who thought their cold brew was too light or lost body, we recommend increasing the level of agitation.
Keep in mind that we are brewing a concentrate. Another way to adjust the TDS, body and mouthfeel of your cold brew is to adjust the dilution ratios to perfect your ready-to-drink offerings.
Tomorrow, we will tackle Duration.