Reference for Pesachim 79:5

ר' יוסי אומר שורן בחומץ וחומץ צומתן אמר שמואל אין הלכה כר' יוסי

barley on Passover; and if one did wash [them] and they split, they are forbidden;<span class="x" onmousemove="('comment',' Because then they turn leaven very quickly.');">⁷</span> if they did not split, they are permitted. R'Jose said: He can soak them in vinegar.

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