Using a refractometer during mashing

[devilsbeltbrewing]

Hi just have a question for those who track mash efficiency and brix levels to determine completion of starch conversion. I recently purchased a refractometer to start advancing my homebrews. I am very curious what degree of brix is considered optimal during multiple mash rests?

 

[Iseneye]

That's an unusual question. I use mine to measure gravity - not conversion. People do iodine tests to confirm conversion.

 

[devilsbeltbrewing]

i could be misunderstanding but i was told the best way to track efficiency is to track brix through mash rests, pre-boil and post boil. i have used iodine in the past but figured it would be easier if i could use one tool.

 

[McKnuckle]

Measuring gravity in between mash steps is a bit odd - perhaps interesting but not necessarily practically useful. Now, measuring it at the conclusion of your mash (after lautering, pre-boil) and after the boil - those are the classic gravity check milestones before fermentation.

One reason I wouldn't bother using a refractometer during the mash is because of stirring. It's a finicky device - it only uses a couple of drops, so you need to ensure that your liquid is thoroughly mixed in order to distribute sugars. That's going to be pretty difficult in a mash situation, and your readings might impress you at first but won't prove to be reliable.

 

[broadbill]

So what would you be measuring? I would expect that at the beginning of the mash the refractive index would be high as I would guess that the starch granules and the long chain polysaccarides would increase refraction of light. As it converted to simple sugars the refraction would decrease. Then when you boil you concentrate the simple sugars and the refractive index would increase again. This is only a guess

As far as tracking refraction through multple mashes; who knows if the refractometer would be accurate enought to measure differences. My impression of this is that conversation is very rapid with today's malts, which is why most brewers don't even bother with multiple mash rests/step mashes in the first place.

 

[william_shakes_beer]

I use a refractometer after my mash is complete and I pull the bag, to determine if I need to add any DME to get up to my desired OG.

 

[Bobby_M]

You can track sugar creation throughout any of the sacc rest temps, i.e. the active amylase zones between 142 and 160. Basically calculate your gravity assuming 100% conversion using the grain weight x 36 then divide by how much strike water you used. I've never measured 100% conversion even allowing for some variation in a given grain bill's PPG.