poor sanitation ... not controlling fermentation temperature ... and/or splashing the wort during its transfer to the bottling bucket or bottling are probably to 3 most common causes of a spoiled batch.
- good sanitation requires items to be cleaned ... then sanitized.
- fermentation temperature inside the fermentor should be in the mid-60s (~18°C).
- transfer wort 'quietly' (no splashing)
pix shows how we keep the fermentor cool with an ice bottle and a 48-QT cooler.
keep trying!
few of us had a decent batch the 1st go-round ...