Yeast for beer brewing can be found in both liquid and dried form - both have some advantages and disadvantages.
From a home brewing perspective, the convenience, cost and reliability of dried yeast make it hard to pass up. With more work being done to increase the range of dried Yeasts available, it’s become arguably the best option for those who aren’t making large batch sizes and don’t brew regularly enough for liquid yeast to be viable.
See below for some advantages and disadvantages of each format;
Liquid Yeast
Dry Yeast
Advantages
A huge number of strains are available - this is the main benefit of liquid yeast. Some yeasts can’t handle the drying process, whereas any strain can be collected and cultured in liquid form.
More affordable than liquid strains.
Typically contains a higher cell count per package than liquid yeast.
Has a longer shelf life - roughly up to 3 years at room temperature.
More tolerant of temperature, making shipping less of an issue.
Disadvantages
Significantly more expensive compared to dried yeast.
Very sensitive to heat - if it reaches over 32°C (90°F) it’s destroyed.
Often has a shorter shelf life.
Cell count may be variable - make sure you check the packaging to know how much to add.