Accounts just posted for Harris + Hoole show pre-tax losses more than doubled to £25.6m after a rapid expansion during the 53 weeks to 1 March.
The accounts noted that the company would require £6m in funding from Tesco for the period to the end of 2016-17 in order to meet its obligations.
In addition, Tesco has given a commitment that it will not try to seek repayment of a £48m loan or accrued and unpaid interest in the next 12 months.
The coffee chain reported that it opened 22 new shops during the year, and closed six others, giving it a total of 45 at the year end.
This enabled it to increase revenue to £12.8m, compared with £6.6m the previous year, but the cost of sales increased from £11.7m to £18.6m over the same period.
Operating losses increased from £11.2m to £21.6m. The company reported that this reflected a significant impairment taken on a number of properties and other assets of £9.8m.
The directors said that by the end of the financial year, the majority of shops had turned to profit after their early life-cycle stage.
They noted that the UK coffee market was highly competitive but believed the artisanal approach and differentiated offering of Harris + Hoole meant it was well-positioned to grow sales and market share.