{HEAD ~ The amount} of {TAIL ~ gas} released each time the valve opens is used to determine how much gas is produced during fermentation, in the manner described above 
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{ HEAD ~ The amount } of { TAIL ~ gas } released each time the valve opens is used to determine how much gas is produced during fermentation , in the manner described above
HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH