Another key factor that contributes to filtration was the duration or steeping time. To test this, we did a series of test batches at 12, 16 and 24 hours.
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).
- 12 hours - 302
- 16 hours - 320
- 24 hours - 324
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.
- 12 hours - low sediment
- 16 hours - low sediment
- 24 hours - medium sediment
Conclusion - From our preliminary tests, steeping time has an effect on level of filtration and body. For people who found too much sediment and body in their cold brew, we recommend reducing the duration. For people who thought their cold brew was too light or lost body, we recommend increasing the duration.
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 Temperature.