Instruction: Extract information from the supporting document to answer the given question.

Input:
Question: Is the bottom of this glass concave so it collects water in the dishwasher?
Document: This is a wonderful glass for everyday use. It is comfortable to hold and has a substantial feel to it. Classical styling goes well with everything. Looks great right out of the dishwasher. I give it an unqualified recommendation. May be slightly heavy for very young children, who probably should be drinking from plastic cups anyway.
I read some reviews and was very happy with the price of these glasses. They are a very heavy glass and maybe too heavy for every day use. They even weigh down my dishwasher a little too much. Some reviewers said they were stackable, but I tried & they got stuck. You have to be very careful stacking because you can break them if you stack and then try to unstack. However, Libbey is very good in responding and replacing items for breakage, even when purchased from Amazon.
I bought the 18 piece set from Amazon about a year ago. Half of the glasses have broken in the dishwasher. I have other glasses that have held up in the dishwasher for 15 years without breaking. Both types of glasses have been treated exactly the same way, so there is definitely something wrong with the strength of the glass in these. They are made from thick but fragile glass. If you hand wash your glasses, I'm sure they would be fine. If not, avoid them.
Nice heavy clear glass. I had an old set (probably not exactly this model) and those fit together much better.
Love this glass. It is perfect for everyday used! Solid, aesthetic wise. No chips or cracks. Very well packed! Would recommend it.
I like this set of glasses. They are solid glasses. I like the price. I just wished there was a 24 oz glass in the set.
I love my glass set It was exactly what I wanted the quality is very good and I am pleased. The set was package in a way that broke two glasses other than that I am enjoying my glasses.
(And it didn't make sense for me to return an entire 18 piece set for just one broken glass.) Looking back, I think I would have chosen a different set if I could because these are just too heavy of a set.
I am a med school student and found that these glasses were extremely nice for us. They are heavier than normal drinking glasses so they are more durable. They do not break as easy as other glasses. We enjoyed how many glasses you get for a cheap price. Easy glass is the perfect size.
I've probably broken more of these than I've bought, but I'm pretty rough with my glasses. But these are nice because they are cheap enough and they also look okay on my dinner table. The smallest one is also my favorite because it's just perfect for that aperitif at the end of a long day. If you have kids and need a cheap, decent-looking and very functional glass (they sit well and are sturdy), then definitely give these a go.
Answer: No. No problem collecting water.