What scent does bioethanol have?
You can read about it in this blog.
Bioethanol, sometimes also referred to as bioalcohol, does not burn by itself. The gas that is released from the evaporation of ethanol burns. This is also the reason why an ethanol fireplace 'warm up'. The colder the temperature, the lower the evaporation, and consequently, the lower the flames.
Bioethanol is derived from plant residues. There is no distinct odor released during combustion, although many users may perceive something. It makes sense as something is being burned. Similar to a wood-burning stove, oxygen is being depleted from the room, and you'll notice this without proper ventilation. Think of the oxygen levels at a high mountain peak.
For ventilation, it's not always necessary to open a window. Mechanical ventilation, leaving an interior door open, or using a window vent can often suffice. Ultimately, the extent of combustion determines the level of ventilation required. If a very large burner is used in a very small space, adequate ventilation is crucial.
Ethanol is derived from various crops, with maize or corn waste being common sources in Western Europe. The scent can vary from person to person, but ethanol derived from maize might have a faint sweet odor at most. A scent that's hardly noticeable..
Ethanol is never 100% pure. Additionally, bioethanol needs to be denatured (a process to render ethanol unfit for consumption). After denaturing, bioethanol contains around 95-97% pure ethanol (alcohol). This is called 100% pure bioethanol. Bioethanol with a lower percentage is diluted with water or has other additives.
Adding a scent to ethanol might seem like a good solution. However, scents are always oil-based. Ethanol combustion is clean, while oil combustion is not clean and leaves residue. Aromatic or essential oils can be placed in an aroma stone or used with a diffuser next to the burner.