Brewing coffee concentrate using both hot and cold methods - Freezing concentrate

Question

I drink iced coffee by the gallon. Currently my go-to method is just to brew a strong pot of store-brand medium grind coffee at night using an old Mr Coffee drip coffemaker, putting the brewed coffee in the fridge and adding sugar-free hazelnut syrup and fat-free half & half in the morning.

Obviously, I'm not a coffee connoisseur. I'm not looking for exquisite flavor and delicate notes here, I just want my java, and I want it as cheaply and conveniently as possible. I don't want any "nasty" flavors, and I can't stand burnt tasting coffee, but I won't even notice a reasonably mild decrease in quality.

I've read about brewing methods using near boiling water (french-press type), and cold brewing methods to make concentrate. Can I get more bang for my buck by doing both? What I am imagining is using my 10 cup rice cooker and the giant freezer I have at my disposal this time of year. How about freezing the concentrate in hopes of keeping it at the ready for 2-3 weeks?

This is what I have in mind:

Step 1 - In the morning, put a large quantity (maybe 2 cups?) of inexpensive, medium roast, medium grind coffee in my rice cooker. Add 8 cups of cold water, hit "cook" and bring just to or just below the boil.

Step 2 - Perhaps keeping the rice cooker on "warm" for a while? My cooker will drop from boiling down to about 140F where it will stay just about indefinitely.

Step 3 - Set the cooker insert, contents and lid on the porch until chilled, then place in refrigerator overnight.

Step 4 - Strain the grounds from the coffee concentrate, freeze the concentrate in ice cube trays. Once frozen, transfer cubes to a freezer bag.

Step 5 - Reconstitute coffee cubes in water, add syrup and creamer.

Can I expect that I will get more concentrate (or more concentrated concentrate) by using both heat and time in this way? What problems can you foresee? Should I keep it below the boiling point? Will keeping it warm for a while extract more flavor? Will it be OK to freeze the concentrate?

Answer 1

I think this will give you some very disgusting coffee. By doing both a high temperature and a long extraction, you will get the worst of both worlds.

High temperature extractions can get some great flavors out of coffee by forcing out a lot of the caramelized sugars, but usually they also use a very quick extraction to avoid also pulling out the bitter flavors.

Cold brewing works by remaining below the temperature that the bitter compounds are most easily extracted at and using a long extraction time to get out the most of everything else.

By using a high temperature and a long time, you'll get most of the sugar out, but you'll also very efficiently extract all the bitter compounds in your coffee.

I would think your best bet for something like this would be to just use a standard cold brew method. Let the grounds sit in room temperature water from 12-24 hours, strain it through cloth (I like using a clean old t-shirt), and then refrigerate your concentrate. I also know people who have frozen the concentrate in ice cube trays to use in blended drinks, so it should freeze well too.