Tell them it's good and drink it. Anything is good, relative to feremented camel urine and coconut milk (that brings back memories). Then, offer them one of yours:
If yours is better and they notice, and they ask how to improve theirs, give them advice. If yours is better and they don't notice, let them be happy with what they have achieved -- if they tried to "improve" they wouldn't notice the difference, and would be wasting their effort.
If yours is better, and they think that their's is better: there's no accounting for taste. You drink yours, and they drink theirs and talk about the beauty of beer paradoxes.