For a 27-minute audio file that you cannot transcribe yourself, there are several free options available online. Kapwing is a free audio-to-text converter that allows you to simply upload your audio file and generate a transcript. The process is straightforward - you click the Upload audio button, select your file, and then Kapwing will provide you with a full transcript that you can review and edit as needed.
Another free option is Flixier, which also offers a web-based audio-to-text conversion tool. You simply upload your audio file, and Flixier will generate a transcript for you quickly and easily, all within your web browser. There's no need to download or install any software. Additionally, services like Notta and Descript provide free audio transcription, allowing you to convert your 27-minute audio file to text without any cost.