Tseem ceeb roj yog lub essence ntuj ntawm cov nroj tsuag, yog li nws cov yam ntxwv muaj xws li: volatile, lub teeb tiv taus, kub tiv taus thiab lwm yam. Yog li, nws yuav tsum xaiv nws tus kheej ntim kom yooj yim nws txoj kev khaws cia. Cov khoom siv ntawm cov hwj tseem ceeb feem ntau iav, thiab cov tuab ntawm lub cev lub cev yuav tsum yog kom ua kom ruaj khov.

Kev ua tau zoo cov roj fwj yuav tsum tau mus rau qee qhov qhov siab qhov siab. Qee cov roj tseem ceeb tseem ntim tau tseem ntim rau hauv cov yeeb yuj pob tshab iav, tab sis qee cov muaj kev cuam tshuam rau kev ua kom tsis txhob muaj teeb.

Cov fwj iav yog qhov ruaj khov thiab tsis yooj yim hnov ​​nrog cov roj tseem ceeb. Txawm li cas los xij, cov hwj yas zoo nkauj, suav nrog qee cov hwj yas ntim ntim, tsis zoo. Thaum muaj cov roj tseem ceeb, qee cov khoom phom sij tau sib cais tau yooj yim, vim tias cov roj tseem ceeb yog qhov ruaj khov yog qhov ruaj khov.