While on the whole, wine and spirits are a relatively low-risk asset class, there are certainly factors to consider before investing.
Spoilage
Perhaps the biggest risk is spoilage, particularly for wine, though spirits can also spoil if stored improperly. For wine, it is of vital importance not only to store it properly, but to not hold onto it past the optimal point of drinking. Unlike spirits, wine will not last indefinitely, and if an investor waits too long to sell, it may see its value drop.
Reduced Demand
While wine and spirit consumption is still on the rise in the U.S., the market for investment-grade wines and spirits tends to operate independently from the overall trend. As a much smaller market, changes in demand for high-end bottles can have an outsized effect on the market. This applies to the market as a whole, but also for sectors of the market - while there is no reason to believe that Bordeauxs or Burgundys will see lower demand going forward, certain trends can disrupt other emerging markets.
Damage in Transit
Of course, there is always the risk that your bottles could be damaged in transit or while in storage, so be sure to pick reputable storage and shipping companies and always make sure to have insurance.
Fraud
There have also been some very notable scams and fakes, particularly in the wine industry. In some ways this has made the market more secure as retailers and auction houses are now more vigilant about provenance, but if something seems too good to be true, be careful.