What Are the Differences Between Cold Brew and Iced Coffee? How Long Can Cold Brew Coffee Concentrate Last in the Refrigerator?

FrontStreet Coffee recently came across a discussion asking, "What is the difference between ice-brewed coffee and cold brew coffee?" The replies varied, with some saying there is no difference and others joking, "For coffee made by my hands, whatever I say it is, that is what it is." So is there really a difference between the two?

What is Ice-Brewed Coffee?

Ice-brewed coffee is essentially cold drip coffee. Ice brewing means drip-extracting coffee grounds with an ice-water mixture below 1°C. A typical cold drip maker has three parts: the upper chamber holds the ice-water mixture, some with a valve to adjust the drip speed and others preset by design; the middle chamber holds the grounds; and the lower chamber collects the extracted coffee liquid.

Extraction Time for Ice-Brewed/Cold Drip Coffee

Because the ice-water mixture is so cold and the method is drip extraction, flavour compounds release slowly from the grounds, which makes bitterness and off-flavours hard to extract. To ensure the sweet and sour flavours come through fully, the ice water should drip at 4 drops every 10 seconds, with a total extraction time of 4-8 hours.

Once extraction is complete, you cannot drink it straight away, because at this point the coffee has little flavour left to show. It needs to be sealed and left in the refrigerator for over 8 hours. The sealing process produces carbon dioxide, and the pressure from that CO2 lets the flavour molecules express themselves better, a mellowing step. Cold drip coffee overall feels light, genuinely clean, refreshing, and free of impurities, with abundant aroma that is a real pleasure.

What is Cold Brew Coffee?

Cold brew coffee, also called cold steep coffee, means pouring cold water over coffee grounds for immersion extraction. The cold steep method can amplify the flavours and aromas in coffee, reduce acidity, and enhance overall body. The equipment could hardly be simpler: a lidded container and a filtration tool are enough, so you can make it anytime at home or in the office.

Should Cold Brew Coffee Be Extracted at Room Temperature or in the Refrigerator?

Both work, but the extraction times differ. Cold brew at room temperature should not steep for more than 8 hours, while cold brew at low temperature is best steeped for 12-24 hours.

Room-temperature cold brew varies in extraction time with the room's warmth. Coffee steeped at room temperature shows fullness immediately after extraction, but the downside is that if the time does not suit the grounds, they will release woody flavours in protest.

The advantage of the refrigerator is that it extracts fullness while making woody flavours less likely to appear, but the disadvantage is that it takes a really long time. Low-temperature extraction makes off-flavours and bitterness hard to draw out, yet the process is still slow. To keep the resulting liquid from becoming too concentrated, it is best to adjust the grind slightly coarser.

Coffee Bean Selection

On bean selection, FrontStreet Coffee suggests choosing coffees with different processing methods or roast levels according to preference, as long as they are within their optimal flavour period of 2 months. Cold drip extraction highlights wine-like aromas, fruit fermentation notes, and sweet-sour aromas. If you like clear fruit aromas, FrontStreet Coffee recommends cold drip made with Flower Butterfly coffee beans, which present the sweetness of pomelo tea.

If you like fermented wine aromas, FrontStreet Coffee recommends Honduras Sherry Barrel cold drip, with rich whiskey and vanilla on entry and a honey-like sweetness.

And if you prefer full acidity with a juicy sensation, FrontStreet Coffee recommends sun-dried Guji cold drip, with lively berry and passion fruit sweet-sour notes, obvious juice-like quality, and a clean tea-like aftertaste.

How Long Can Ice-Brewed/Cold Drip Coffee and Cold Brew Coffee Be Stored?

Once extraction is complete, ice-brewed or cold drip coffee can be sealed and stored in the refrigerator for 3 days. As time passes, the flavour weakens after three days and the taste turns very light.

Cold brew coffee, after filtration, can be sealed and stored in the refrigerator for 5 days. Although cold brew grows richer the longer it is stored, a refrigerator is a complex environment, especially a household one, and bacterial contamination is hard to avoid. It is therefore really not advisable to store it a week, let alone a month, before drinking.

FrontStreet Coffee Recommendation

Choosing the right bean is what separates an ordinary cold brew from a memorable one, and FrontStreet Coffee roasts several that suit low-temperature extraction. The Strawberry Candy blend pairs Panama Geisha with Costa Rican honey processed coffee, one side bringing delicate rose and orange, the other grape, dried blueberry, and strawberry fudge sweetness; cold brewed, it is sweet and lively, and after a little fermentation it takes on a fruit-wine quality. If you like a strong floral nose, the Huakui comes from Ethiopia and, being natural processed, absorbs plenty of sweetness from the fruit, showing magnolia, cream strawberry, mango, guava, and red tea in cold brew.

For a juicy, fruit-forward cup, the Kenya Cherry Tomato is a natural fit: from Thika in Kenya, planted at 1550-1750 metres, it uses the SL28 and SL34 varieties and the region's 72-hour double washed fermentation, so cherry tomato, snow pear, black plum, and dark plum acidity come through clearly in the cold, with low bitterness and a long finish. The Colombia Sidra, double anaerobic natural, adds passion fruit, blueberry, grape, and apricot with a juicy, clean body. Making it is simple: FrontStreet Coffee suggests 30g of coffee ground to fine sugar, a 1:12 ratio with 360g of room-temperature water, eight hours in the refrigerator, then filtering and returning the liquid to the fridge for three more hours to mature.