Instruction: Generate an answer to the question by utilizing the information contained in the document.

Input:
Question: What type of coffee do you put in this? Regular? Instant?
Document: I really love this product! I bought the refillable PRESTO brand before and it caused the Senseo coffee maker to leak and just generally made a big mess every time I used it. This one fits right in and you put about a tablespoon of coffee in it, put on the cover and it makes wonderful foamy coffee from your regular brand of ground coffee. You also don't have to have any paper filters like you do with the PRESTO. I highly recommend it.
Unit seems nice but leaks, even with no coffee in the unit. Retains a lot of liquid. My senseo is a correct type for this unit so it was disappointing.
I broke down and bought a Senseo coffee maker. I waited so long because the pods are expensive and I like switching out flavors and brands. But the CoffeeDuck works as advertised! I can enjoy any type of coffee. No more paying $1 a piece (or more) for coffee pods. Don't buy a Senseo without this accessory.
Works great, unlike other purchases I made here for this type of product.Fast service.Love that I can use my espresso grind in it for cappuccinos.
After having bought the CoffeeDuck, used it, and become disappointed with it, - I am in love with it again. I LOVE the Senseo dark roast coffee pods, they taste like coffee in Holland, but they are NOT cheap. All hands down - If you like this type of coffee flavor - go to Ikea and buy a bag of their ground espresso coffee. It is FAR cheaper than the coffee pods.
I have had my Seneos (2) for several years. Although i have found pods that i like, I really enjoy a particular type of Hawaiian peaberry coffee. My husband found the refillable filter and I love it. I completely fill the cup of the filter with ground peaberry, run the 2 cup button, then hit it again for another couple ounces, and it fills my travel mug with a strongish version of my fav coffee.
I have been using this item for almost a year. I am disabled and usually homebound - but I like good coffee, hate using pods, and have a senseo. What a great product! Never any problems unless coffee ground too fine or overfill the pod - then water spitting all over kitchen! Doesn't matter what type of sale coffee I use - still great! I do microwave the milk in my mug first though for hotter coffee. Highly recommend!
In the US, Senseo-type pod choice is limited and pods are unnecessarily expensive. After exploring the options, I opted for the Duck, and am thoroughly pleased. We use the very inexpensive bricks of espresso grind coffee marketed to US latinos (such as Bustelo) and readily available at most all grocery stores in the US. The fine grind makes a very creamy froth and for almost 8 months we have used the duck every day for at least two mugs a day and have never been disappointed.
Love this thing.I've had my Senseo for years and years...well made...top quality...but the regular pods just aren't good. It's surprising that the coffee is so second-rate because the machine is so well made.
I use Caffe Kimbo gold medal or Lavazza espresso. When you fill the coffee duck, make sure you leave 4-5mm space on the top and even it out. No need to tamp it down. I prefer the European style stronger coffee, not the weak diner/pancake house type. I press the single cup and then fill the coffee duck again and press the single cup again. Use a knock box to keep all the coffee grounds from dripping all over the kitchen floor.
Answer: With all due respect, as a real coffee drinker instant coffee does not even come in my house. You need a fine grind absolutely not the ground coffee for a regular old coffee machine; water just runs through the grains rather than sit on it and slowly drip through. It's needs to be fine (not Turkish coffee fine but close). You can buy any coffee you like, Joe's brand or Starbucks, whatever. I buy the Seattle Mountain brand Colombian Supremo at Costco. It's a 100% Arabica bean. Excellent. Also comes in decaf if you so desire. Grind at Costco machines at "fine" setting, I believe 4 steps away from the left. I'm pretty picky about my coffee because I drink only 3 small cups a day so it has to be good!  Good luck.Also' I vacuum pack and freeze my coffee as as I get home since I'm the only coffee drinker in this house. I make bags of approx. 250gr (about 8 oz) and keep in freezer. I keep the "in use" coffee in airtight container.