Question:
If one is listening to kiddush over whiskey, may one call out l'chaim after the person making kiddush says savri but before he makes the bracha shehakol or is this considered a hefsek?
Answer:
Your question is only relevant to Kiddush Shabbos morning, because we don’t make Kiddush on whiskey at night. The daytime Kiddush technically is only the actual bracha, and not even the pesukim that are said before it, therefore if he spoke out before the bracha was said it isn’t a hefsek.
Sources:
M:B 272-27, 289-2.