How to generate a valid hash for a bip39 seed phrase?
You can create a valid seed calculating a valid last word (23+1).

Even using the browser JS console:

mywords="sausage liquid same heart ... "

allwords = WORDLISTS["english"]
m = new Mnemonic("english")
for (var w in allwords) { 
       curr_word=allwords[w]; 
       test_words = mywords + " " + curr_word; 
       if (m.check(test_words)) { console.log(curr_word) } 
 }


Source: 

http://wikistas.com/u/cryptodog!Ccsi1HdXWr/Wd5q-generating-secure-bip39-seeds