Effectiveness of Quick Pulls

This means adding the solvent to the soup soon after the ingredients have been mixed (i.e salt, lye and acidifed root) & brought to the correct temperature, (20°C for naphtha and mid 40s or higher for heptane).  By "soon" we mean as little as a few minutes or as much as an hour). It also means pipetting out the solvent immediately upon layer separation and performing subsequent pulls without delay. This may sound counter-intuitive but has repeatedly proved effective. 

Note that "quick cold pulls" are equally valid for all solvent types mentioned for DpTek1. In particular, heptane can be used at room temperature without issues. However, If used for "re x", then heptane needs heat because the crystals are already formed and extra heat is needed to dissolve them. For extraction, the transfer of the product doesn't involve dissolution of formed crystals and appears to make no difference if heptane is used at room temperature.

Test 1 : Quick 20°C Pull (with naphtha as described above) vs SVH 24h Mixing Scheme (performed by ML)

Conditions

In this test, a 200g finely shredded root sample was acidified and put through a single cycle of freeze/thaw.  Upon the first thaw it was finely blended to a paste, and then divided into two equal samples.  Both were then treated identically (including 2 more freeze/thaws), except that one  was subjected to the usual cold, quick pull and the other the SVH-recommended 24 hour mixing scheme.  Results for yield and apparent purity were as follows.  Note that the thrird pull on both samples yielded no purity flakes, just an unknown brown  substance with an oily texture

Conclusions

The quick, 20°C pull produced a significantly larger yield which was also visually whiter and did not have noticeable patches of stained yellow flakes.   

Additional tests will be needed to substantiate the results, but the test is not an easy one to perform without a magnetic stirrer or similar.