Extract efficiency VS starch conversion?

[Mr. No-Tip]

I was thinking today and realised I have a bit of a gap in my understanding about extraction vs conversion.

Today I did a pils and decided to not treat my water given we have such a soft pilsenish base in Canberra. I added 4% acidulated to help with the pH, but it's been a long time since I've brewed without salts, or at least the pH5.2 buffer. I did a starch conversion test at mashout and all was good, but my efficiency barely 60% - at least 10% less than I am used to.

It made me realise something that is probably rather obvious. Extract efficiency and starch conversion are in fact different things. Unconverted starch will make our hydrometer float just like sugar will, so when we're talking efficiency, are we effectively talking about starch extraction, and the conversion itself is (hopefully) just a given?

Perhaps I need to go back to Palmer - it's been a while.

 

[Ducatiboy stu]

Eff is starch conversion and how well you can rinse out da sugaz

 

[Mr. No-Tip]

That doesn't really make sense in the context of my experience.

None of my brews have unconverted starch, yet the extract differs significantly. This suggests there is a 'starch availability' factor ahead of conversion and rinsing.

Unless the pH prevents rinsing of already extracted sugars, but I am not aware of anything in that vein?

 

[JDW81]

In simplest terms if your grains are all wet at an appropriate temperature in an appropriate amount of water then you will get full conversion quite quickly. The majority of modern malts are highly modified and will convert the starches to sugar given the correct temperatures. However, conversion doesn't equate efficiency. Conversion is mainly reliant on (but not limited to) grain crush, mash temp and time.

Efficiency looks at how much of the potential of the grain you are able to extract, assuming you get 100% conversion. You can have 100% conversion but still have crappy efficiency. Factors affecting extraction include (but again not limited to) your mash tun design, particularly the collecting system at the bottom, sparge temperature, sparge method, sparge speed, grain bed depth, grain crush etc. Of course your efficiency will be down if you don't get 100% conversion, but unless you are doing something very odd it is rare, even for home brewers to not have full conversion with good mashing technique.

Things like pH, mash regimen and the types of grain used all play a role in both, but really only a small role compared to the factors mentioned above.

JD

 

[Ducatiboy stu]

You can have large chunks of whole grain that will fully convert, but you are unable to rinse da sugaz out of the grain. This is why your crush is important.

You could rinse all da sugaz out eventually, but you will need a lot more sparge water to do this.

Eff is prob a bit misleading. Its more a case of " how much sugar you can rinse out with a given volume of water".