From a large bottle containing 1 liter of alcohol, pour out $\frac{1}{3}$ liter of alcohol, add an equal amount of water to the bottle and mix well, then pour out $\frac{1}{3}$ liter of the mixture, add an equal amount of water and stir again, finally pour out 1 liter of the mixture, and add an equal amount of water. At this point, the bottle contains $\qquad$ liters of alcohol.
【Analysis and Solution】  
Each time it is poured out, the remaining alcohol is $1-\frac{1}{3}=\frac{2}{3}$ of what was there before; finally, the alcohol left in the bottle is $1 \times\left(\frac{2}{3}\right)^{3}=\frac{8}{27}$ liters.