Let's talk numbers. A standard espresso dose is usually 18 grams in, 36 grams out, in about 25–30 seconds. But those numbers are a starting point, not a law.

In cold weather, your water might be cooler, so you might need to pull a slightly longer ratio to get the sweetness out. Try 1:2.5 instead of 1:2—that's 18 grams in, 45 grams out. It sounds like a lot, but it can push the extraction further and turn bitter into balanced.

If your shot is running too fast, like 15 seconds, that usually means you need a finer grind or a higher dose. If it's running slow, like 40 seconds, go coarser. But here's the thing—if your water's too cold, the shot will be fast AND bitter, and grinding finer won't fix it; it'll just make it bitter and slow. So, always check temperature first.

One more thing: keep an eye on your yield. If you're not using a scale, you're guessing, and in winter, that guess is probably wrong. Weigh your shots until you get a sense of what's happening. It's the only way to know if you're under-extracting or over-extracting.