Sentence:  This in the second boiling will be replaced by nearly an equal quantity of worts, of the same gravity as turned out of the copper, which, in making the calculation, is to be deducted from the <WSD>aggregate</WSD> of the second worts, and so on with a third wort if necessary. 
Meaning of the word marked with <WSD> tags:  A mass formed by the union of homogeneous particles; – in distinction from a compound, formed by the union of heterogeneous particles.