Saturday morning, at the first batch, the forecast gives 11 degrees and gusts from the north. Sunday, at the same hour, 8 to 9 degrees and almost still air. Laurent roasts the same origin on Golden, with the same taste target, both mornings. Then the coffee lot weather goes onto the bag's page, right next to the coffee roast date. Below you'll find the forecast and a simple test for the day you open a new bag of coffee.
This weekend's coffee lot weather, read on Friday
We checked the Brussels forecast on Friday morning against two sources: the Royal Meteorological Institute of Belgium (RMI) and Open-Meteo.
On Saturday, between 7 and 9, the forecast gives around 11 degrees, with 82 to 87% humidity. The wind will blow from the north-northwest and gusts may go past 35 km/h around 8 o'clock. Open-Meteo shows a few drops around 8, about a millimetre, then a dry day. The afternoon should climb to 14 or 15 degrees.
Sunday morning will be colder: 8 to 9 degrees at 8 o'clock, around 80% humidity, light wind under 8 km/h, dry. The high will stay around 11 or 12 degrees. Pressure will sit near 1024 hPa on both days, so we expect no surprises from that side.
What each condition asks of the roaster is covered in the article on temperature, humidity and wind. For this weekend: on Saturday the wind pulls at the flame, so Laurent will work with the windscreen and small gas corrections. On Sunday the cold, still air will call for a longer warm-up of Golden before the first batch. The taste target stays the same on both days.
Where to find the coffee lot weather after the market
On meteokoffie.com, each coffee's page shows the roast date, the lot code and a line with that day's weather. The Ethiopia and Brazil pages currently read: roasted on 11 October 2026, sunny, 13°C, 89% humidity, 1020 hPa, wind 4 km/h. The Ethiopian lot code, MK-261011-SNM-ETH, starts with the same date, written year, month, day.
This is what we call Weatherroir: same origin, same roaster, same taste target, a different sky every time. Laurent reads the weather and adjusts fire and time so the lot reaches the target. Fine differences can remain between lots, and we explained them in the article on lots from the same weekend.
For you, that line has a very practical use: it tells you that you've moved to a different lot. And when the lot changes, your recipe deserves a five-minute check.
The new bag test: coffee lot weather next to your recipe
The grinder setting you found for the old bag is the starting point for the new one. The steps, in order:
- Write on the old bag with a marker: the roast date, the weather line and your recipe. For an espresso recipe at home, the base is 18 g in the basket and 36 g in the cup, plus the seconds. For filter: 15 g of coffee to 250 g of water, the grinder step and the total time.
- Keep the last 30 to 40 g of the old bag until the new one enters its window. A bag roasted this Saturday is ready for filter on Wednesday and for espresso the following Saturday, following the resting rule by method.
- On the same morning, brew one cup from the old bag and one from the new, same recipe, same setting.
- Compare the time first, then the taste. Change one thing only, usually the grinder, by one step.
- Write on the new bag the step you landed on, under the lot's weather.
What the first cup tells you
- The time is almost identical (2 to 3 seconds apart for espresso, 15 seconds for filter): keep the recipe as it is. If you still taste a new nuance, you've found the fine difference between two lots.
- The espresso runs much slower, with very thick crema: the new bag is still too fresh. Wait two or three days before you touch the grinder, because thick crema gives away the bean's age.
- It runs faster and tastes sour: one step finer.
- It runs slower and tastes bitter, even though the bag has rested: one step coarser. The signs are in the article on grinding too fine.
After three or four bags you have your step for each origin on paper, with each lot's weather beside it.
On Saturday and Sunday we're at Marché de l'Abattoir, by the Manufakture car park exit in Anderlecht, with coffee roasted outdoors right in front of you. Bring your old bag with your notes on it and ask Laurent what changed at the fire on the morning of your lot. If you can't make it for coffee at Marché de l'Abattoir, you'll also find freshly roasted coffee in Anderlecht in the online shop, with the weather written on every page.
Brut. Sauvage. Imprévisible.
