All street heroin is impure. I don't really think differences in duration of effects are due to "differences in the actual diacetylmorphine".
So, we have a number of types of street "heroin":
1.
powder heroin hydrochloride - Diacetylmorphine salt + can contain varying amounts of impurities from manufacturing depending on whether it was properly refined + cuts.
2.
tar heroin - What makes tar specific is the use of an antiquated process to make it, which produces a relatively unrefined product resulting in greater amounts of other morphine derivatives, such as 6-monoacetylmorphine (which is active) and 3-monoacetylmorphine, and perhaps some unreacted morphine (and who knows what else).
3.
tar heroin that has been turned into a powder by mixing it with cut (appearance-wise can sometimes can be very hard to tell from regular powder heroin, except that tar heroin made into powder is not likely to be
pure white whereas sometimes heroin hcl powder dope can be pure white)
4.
base heroin (but we'll exclude this as it's rare in North America)
Potential factors:
- impurities from the manufacturing process as mentioned above
- added "inactive" cuts
- added active adulterants, such as: other opioids, drugs added to potentiate the effects/reduce the rate at which the body breaks down opioids, or other drugs added (to make it more smokable, to enhance nasal absorption, to make it more stimulating, whatever)
- potency: if you have a higher percentage of actual heroin in your dope and use the same amount by weight, that is obviously going to get you higher but the noticeable effects will also last longer.
Perhaps the reason why different batches have different feels is just how it's processed/ the original poppy plant used. It could be like how some weed has more sativa properties and others have more indica...
No. Whether or not it's properly processed, yes. The poppy plants used, no. There are a lot of steps between poppy and heroin, it's not like weed. Hard to explain more but think about the fact that morphine is made from poppies and it doesn't vary depending on the plants used. We're not talking about raw opium here but a drug that is synthesized from morphine