Cafes have now been defined as establishments which sell "non-alcoholic, drinks, snacks and light meals" as their primary business activity, in new Scottish Government regulations.
This could, though, include cafes with a liquor licence, which will be allowed to stay open if they stop selling alcohol.
The First Minister told the daily coronavirus briefing today the publication of this definition now "doesn't allow a restaurant to turn itself into a cafe”.
Cafes with a liquor licence were initially facing closure in central Scotland under the plans unveiled by Ms Sturgeon this week, but the Scottish Government later agreed an exemption allowing them to stay open from 6am to 6pm if they agreed to stop selling alcohol.
But it has resulted in confusion with suggestions that restaurants facing closure in central Scotland from this weekend could be able to class themselves as cafes and remain open if they stop serving alcohol.
"I want to address a frustration about what some see as a lack of clarity over the exemption for cafes which are being allowed to stay open, even in the Central Belt, during the day as long as they don't serve alcohol," Ms Sturgeon said.
The First Minister said the exemption was put in place to allow cafes which may be the only one in remote towns or villages to remain open to offset social isolation.
But she insisted the broad volume establishments where people gather must close to tackle the spread of the virus.
"That's why we're not allowing premises like restaurants to decide to just stop serving alcohol and become cafes and stay open,” she said.
"That would undermine the purpose of these restrictions.
"But we did realise there was a potential anomaly for existing cafes that have an alcohol licence even though serving alcohol is very, very incidental to their business.
"In some areas, particularly rural areas, they may be the only cafe in a village so we decided to try to resolve this in a very targeted way.
"In the 24 hours we have been doing so I readily accept that that has resulted in a lack of clarity, but sometimes that's the price we have to pay right now for trying to be as flexible as possible."
The First Minister insisted that most establishments would know if they were cafes or restaurants. If they are unsure, they should check with local environmental health officers - or close down to be safe.
The new guidance published by the Scottish Government today sets out a definition of what constitutes a cafes. It states: "An establishment whose primary businesses activity in the ordinary course of its business is the sale of non-alcoholic, drinks, snacks or light meals."
The First Minister added: "I think business owners will know whether their establishment fits that definition or not, but any doubts or questions that any have should be discussed with local environmental health authorities."