▁st arter ▁micro organ isms . ▁ ▁Che eses ▁can ▁be ▁class ified ▁according ▁to ▁a ▁variety ▁of ▁features ▁including ▁rip ening ▁characteristics , ▁special ▁processing ▁techniques ▁( such ▁as ▁ch ed d aring ) ▁or ▁method ▁of ▁co ag ulation . ▁Ac id - setting ▁is ▁a ▁method ▁of ▁co ag ulation ▁that ▁accounts ▁for ▁around ▁ 2 5 % ▁of ▁production . ▁These ▁are ▁generally ▁fresh ▁che eses ▁like ▁c ott age ▁che ese , ▁qu eso ▁blan co , ▁qu ark ▁and ▁cre am ▁che ese . ▁The ▁other ▁ 7 5 %, ▁which ▁includes ▁almost ▁all ▁rip ened ▁che eses , ▁are ▁ren net ▁che eses . ▁Some ▁che eses ▁like ▁ric otta ▁and ▁z iger ▁are ▁made ▁by ▁first ▁he ating ▁the ▁milk ▁to ▁between ▁ 9 0 - 9 2 ▁degrees ▁Cel si us ▁to ▁create ▁cop reci p itation ▁of ▁case in ▁and ▁whe y ▁protein ▁before ▁addition ▁of ▁la ctic ▁or ▁cit ric ▁acid . ▁ ▁Production ▁Trad itional ▁c ott age ▁che ese ▁can ▁be ▁made ▁without ▁any ▁co ag ulating ▁en zym es , ▁though ▁modern ▁processing ▁techniques ▁often ▁do ▁make ▁use ▁of ▁such ▁en zym es ▁to ▁increase ▁yield ▁and ▁reduce ▁processing ▁times . ▁These ▁methods ▁produce ▁a ▁mil der ▁and ▁swe eter ▁flav ored ▁che ese ▁then ▁the ▁traditional ▁method . ▁Ren net ▁is ▁also ▁sometimes ▁used ▁in ▁the ▁processing ▁of ▁other ▁fresh , ▁soft ▁che eses ▁like ▁from age ▁fra is , ▁but ▁it ▁is ▁not ▁an ▁essential ▁ing red