Brewers need it on the Fourth of July, by the way (5)
I believe the answer is:
yeast
'the way' is the definition.
Although both the answer and definition are singular nouns, I can't understand how one could define the other.
'brewers need it on the fourth of july' is the wordplay.
'brewers need' becomes 'eas' (I can't justify this - if you can you should give a lot more credence to this answer).
'it' becomes ''t' (abbreviation. e.g. in 'tis).
'on' means one lot of letters go next to another.
'the fourth of july' becomes 'y' (fourth letter of the word 'July').
'eas'+'t'='east'
'east' put after 'y' is 'YEAST'.
'by' acts as a link.
Can you help me to learn more?
(Other definitions for yeast that I've seen before include "Fungus used in fermenting" , "fermenter" , "Baker's ingredient" , "It makes dough rise" , "Fungi used in bakery" .)