There are a couple ways to look at this. Let's look at just the opportunity cost for the investor. The annualized return of the S&P 500 was 5.35% trailing 10 years, 13.68% trailing 5 years, and 28% over the last year. A 10-year T-bill is currently 2.76%.
If we buy the S&P 500, and it grows at the most conservative rate (5.35%), we'd have 1,178,809 (a gain of 478,809) after 10 years, but that's fairly risky.
Let's assume we buy $700k in t-bills (risk-free) for 2.76%, and take the most conservative S&P rate.
y0 = -700000
y1-9 = 19,320
y10 = 719320
discount 5.35%
NPV = -137,645
We'd lose 138k, so not great, but that's a risk-free loss.
Let's assume we buy 40% of the distillery for $700k.
y0 = -700,000
y1-4 = 0
y5 = 50,000
y6 = 50,000
y7 = 75000
y8 = 75000
y9 = 100000
y10 = 100000
NPV @ 5.35% = -401,453
That calculation assumes you're making $250k net profit by year 10.
If we expand it out to 15 years, and assume the investor will get $150k per year for the next 5 years, the NPV would only be -19,516. So we haven't even broken even yet, and we're assuming we'll be netting $375k per year in years 10+
Meanwhile, the whole time you'd be making a profit almost immediately, since you'd get 60% of the net on your initial investment of $100k.
y0 = -100,000
y1-4 = 0
y5 = 75,000
y6 = 75,000
y7 = 112,500
y8 = 112,500
y9 = 150000
y10 = 150000
NPV @ 5.35% = 347,821
So under that arrangement, you'll triple your money in 10 years, and your investors will lose half their money.
If you end up making a lot more net profit, the investors might see a positive return sooner, but if you adjust for risk, it's probably not worth it. Any way you slice it, you'll end up making a lot more money than your investors will, if you can get them to buy 40% equity for 87.5% of the costs. Plus if the business goes under before year 5, you've got a lot less to lose than they do.