no chaser

Still Alice by LISA GENOVAを読んでいます。
"I'm sorry to tell you, Alice, you're positive for the PSI mutation." Well, there it was, absolute proof, served straight up, no sugar, no salt, no chaser. And it burned all the way down.
"no chaser" の "chaser" とは何でしょう？
・Oxford English Dictionary: A drink taken after another of a different kind, typically a weak alcoholic drink after a stronger one.: 'bourbon on the rocks with a beer chaser’
・Collins Dictionary: A chaser is an alcoholic drink that you have after you have drunk a stronger or weaker alcoholic drink.
週に1回会社の人達と飲む事が毎週の恒例になってきましたが、ビールで始まり、焼酎 and/or ウィスキー、そして最後にまたビールと、まさにこれが "chaser" を飲んでいるのですね。