About The Acidification Stage 

Some teks (Straight To Base STB) use lye to break down the root, but this also results in the release of undesireable impurities which dissolve into solvent and contaminate the end-product flakes. 

For DpTek1, acidification is used to minimise this problem.  During this stage, acid converts Purity Flake material within the root into a salt form which is more water-soluble. Our chemists theorise that this eliminates the need for the lye to break down plant material, thus enabling the freebase Purity Flakes to gain a head-start and be rapidly pulled before other impurities (which the lye also slowly breaks down) have chance to also be extracted from the root.

A complete acidification stage is essential for success in the cold, quick pull process.  Standard white (i.e. clear) household vinegar (marked as 5% acetic acid) has been successfully tested as well as a solution of citric acid (for example 30g citric acid dissolved in 300ml water).  Exact PH does not appear critical.

Note:  It appears probable that if a freezer is unavailable,  leaving the acidified root standing for several days may be a viable substitute to the freeze/thaw cycle (under investigation).  However beware of the possibility of mold forming upon the mix.  A recent report described an acidified sample of 70g root which was left for ~17 days in a sealed flask and several patches of mold appeared on top of the bark/citric acid mix. We have no info regarding safety, but this may be best avoided.