Effective sparging

[domanah]

We have a mash tun with a false bottom. We normally mash with a water to grain ration of 2.5 to 1. When mashing is complete we drain the liquid to the boiler. Then we sparge with half the recommended sparge volume and drain to the boiler. We repeat this once more. With a couple of brews now the end of sparge gravity (after the second sparge) is about 1.024 It seems we cannot get al the sugars "rinsed" off the grain. Anything we should do different. Ideally we do not want to end with more water in the boiler.

[Oginme]

What is your target gravity for your wort from the mash?  Are you allowing the sparge water to steep with the grains for any amount of time?  Do you stir the water and grains when adding in the sparge water?

[domanah]

For this one specific the post mash / pre boil gravity target was 1.042. We add the sparge water on top the grain bed via a sprayball. Then we wait a while for the water to make its way to below the false bottom. We do not stir the grainbed while and after the sparge water is added.

[Kevin58]

That sounds like a thin mash. It may be robbing you of some efficiency in the sparge step. I use a mash anywhere from 1.3qt/1lb to 1.5qt/1lb for my mash ratio. As for your sparge method I would definitely stir then let it sit for 15 minutes or so before draining the mash tun again. Also, if you are not already, I would also stir a couple of times during the initial mash too.

[domanah]

Hello, I should mention the water to grain ratio is 2.5l to 1kg. We will try it next time. Thanks!

[BOB357]

I think everyone assumed the 2.5 to1 was quarts/pound. Much different than 2.5 liters/kg. Normal mash thickness is about 3L/kg, so you should be just fine at 2.5L. In my early days of batch sparging, I did the double sparge thing, thinking that's what BeerSmith was calling for. I later discovered that draining the mash tun was the first of the 2 steps. I doubt that's causing your low extraction. Stratification of the first and second runnings are common. If you haven't thoroughly mixed after the second runoff, that's likely the problem. You're getting a very dilute sample for your gravity check.