The term 'extract' is often used quite loosely - dried and powdered mushrooms are often also advertised as 'mushroom extract' because "the water has been extracted". This is misleading.
Hot-water extraction is the minimum that is needed to free active ingredients from the cell-walls in which they are contained. These cells are made of chitin, an indigestible substance for humans. Most of the active components will simply pass through your body without a trace if you choose the cheap 'extracts'. Eating raw or dried powdered mushrooms has no noteworthy therapeutic effect. Our stomachs work too fast to break down chitin and most people lack the enzyme chitinase, which is essential for digesting chitin.
Read this excellent explanation on the supplement-facts blog.
Oriveda uses state-of-the-art hot-water and/or ethanol extraction and distillation process to get rid of the therpeautically useless chitin and set all the bio-active ingredients free.
After hot water extraction we apply alcohol precipitation. This is a production techique which removes low molecular weight compounds and by doing so increases the level of high molecular weight compounds (research showed high molecular weight beta-glucans and proteo-glycans to be the most effective). The final product with a constant pharmaceutical level of quality and bioavailability is guaranteed. The supplement facts label is again the key to distinguishing the 'real' extracts from the 'fake' extracts: only the first type can specify / guarantee active ingredients.