Thawj kas fes ntawv foldes ntawv ntawv: hais txog cov ntawv lim kas fes uas tsis tau ua kom dawb, thiab lub tshuab lim zoo saib ze rau lub teeb xim av. Piv rau cov ntawv lim kas fes dawb kas fes ntawv, thawj cov ntawv foldes kas fes ntawv muaj tsawg dua, tab sis saj ntawm daim ntawv nws tus kheej tau nce. Nws yog ib qho tsim nyog rau tag nrho tsau lub lim ntawv nrog cov dej npau npau thaum ua kas fes brewing kom txo cov ntxhiab tsw ntawm daim ntawv sau kas fes.
Lim cov ntawv dawb kas fes ntawv: cov ntawv yuav tsum tau siv, nrog kev cai nruj rau cov khoom xaiv, cov txheej txheem, thiab kev tswj kom zoo. Enzyme tshuaj dawb yog siv nyob rau hauv cov txheej txheem tshuaj dawb, uas yog biologically nquag enzyme tshuaj dawb. Nws tau siv dav hauv cov chaw muag tshuaj, thiab cov kev ua mob ntawm kev ua kom muaj peev xwm yuav luag negligible. Thaum siv cov ntawv ntim kas fes dawb kas fes, cov kauj ruam ntawm cov ntawv lim tuaj yeem raug rho tawm tuaj yeem raug rho tawm, thiab cov hmoov tuaj yeem txuas ncaj qha ntxiv thiab yaug.