Next, we tested the impact that temperature has on overall filtration and body. To test this, we did a series of test batches where one was hot-bloomed, one was brewed entirely at room temperature and one brewed at 42 degrees F (all for 16 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).
- Hot Bloomed - 318
- Room Temp - 326
- Brewed Cold - 354
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.
- Hot Bloomed - medium
- Room Temp - medium
- Brewed Cold - medium
Conclusion - From our preliminary tests, brewing temperature had an effect on the TDS but did not appear to affect the level of filtration. One interesting finding was that once the 'Brewed Cold' test was left at room temperature for a time, the TDS dropped below 300 for repeated tests. We will need additional testing to try and understand how temperature can impact cold brew during storage.
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 Manual Extraction.