I just did a 3 Gallon boil with about 100g of hops.

It felt like I left a lot of wort in the brew pot when transferring to the fermenter. It was a struggle to keep the flow in the siphon due to all of the hops at the bottom of the pot.

The gravity reading was a lot below target in the fermenter.

How much of the wort should I be aiming to leave in the brew pot?

What are the best strategies for getting the most wort through the siphon?

EDIT: this was a partial mash brew (2kg malt, 500g oatmeal), with 2kg of LME added for the start of the boil. It was my first partial mash brew, so I need to figure out getting the right gravity from that, but I could see I was leaving a lot of good wort behind in the brew pot and that didn't feel right. I will transfer all the wort to the fermenter next time, and see how the gravity compares to the target. Thanks for all of the advice.

  • 3
    Is this a all grain brew or an extract brew? What sort of ingredients and quantities were being used? Was a grain or hop bag used? Commented Jan 1, 2017 at 13:41

4 Answers 4


Although we need more information to be more specific, the general answer to "how much wort should be left behind" is "as little as possible". One thing you can do is pour the wort through a sanitized strainer and press the hops with a sanitized spoon to extract the wort in them. Also, once the wort is cooled down, you can simply pour it through a strainer into your fermenter. The strainer will stop the hops, and the rest of the trub that makes it through will not only not harm your beer, indications are that it can be beneficial. The reason why your gravity was low will have to wait til we know more about what and how you brewed.

  • I wonder if the gravity was low because he left good wort and had to add too much top off water.
    – uSlackr
    Commented Jan 4, 2017 at 14:10
  • That is one possibility. Or if he did top off (which we don't know) it didn't get mixed thoroughly.
    – Denny Conn
    Commented Jan 4, 2017 at 17:10
  • Thanks, that's great info. I'm sure that the gravity reading was low due to topping up with too much water. It was my first partial mash and I think I got the calculations wrong with it, but the first problem to solve is that I had maybe 3quarts of wort in the brewpot still. I was too concerned about not transferring the hops etc. Next time I will get all the liquid out and not worry too much about the rest getting in. I'll give partial mash another go as well. Commented Jan 20, 2017 at 15:07
  • keep in mind my comment about mixing. I've found that to be the main reason for incorrect gravity readings after topping off.
    – Denny Conn
    Commented Jan 20, 2017 at 16:35

The strategy for getting the most wort into the fermenter is to dump it all in. Everything, hops and everything. I don't scrape the stickies off the wall of the pot, but I tip the whole thing into the fermenter.

I generally aim for none wort to be left in the pot. It will make good beer.

If you're not comfortable with that, the strainer idea is fantastic too.

  • 2
    The hops will settle out in fermentation
    – uSlackr
    Commented Jan 4, 2017 at 14:11

Another easy solution is to use a muslin bag during your boil. Homebrew shops sells them in bulk for under a dollar each. They are like pantyhose and stretch a lot. Stick it in your kettle and clip/tie an end of the bag to either handle. You'll have the bag stretched across the middle of the kettle with the top of the bag open. Whenever you make hop additions, dump them into the bag.

Once your boil is done, just untie the bag and lift it out - the majority of the hop material will come out with it. Hold the bag and let the wort drain from it for a few seconds. Some people say don't squeeze the bag or you'll release bitter compounds. I say don't squeeze the bag because it's really hot and you'll burn yourself and it's not worth it for a half a cup of wort.

I've used these bags when they're included with extract kits and they work very well. They're not reusable but are compostable. There's a small amount of fine hop debris left at the bottom of the kettle, but it's insignificant and can go into the fermenter.

I'd also suggest not siphoning the wort - pour it into your fermenter to get as much yield as possible. Pouring it back and forth between the fermenter and kettle a few times helps oxygenate the wort if you don't have another means of doing so.


If you're not comfortable with the strainer approach (or maybe don't have a sanitised one to hand) and wish to continue with the syphon, could the whirl-pooling technique work here? Stirring the brew pot quickly until a whirlpool effect is created. The heavier elements of the break and other ingredients will gather in the centre of the pot allowing you to syphon nearly all of the wort from closer to the side of the pot.

I believe it's a good technique for extract brewing, but having never tried a partial mash I'm not certain if there may be too many other elements to get a positive effect from this technique.

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