Using refractometer with suspended sediment?

[richl025]

OK, I feel really silly, but I may have been "doing it wrong" for a few years now...

I usually use a refractometer for my SG readings after the mash (BIAB) and of course, post-boil. I would scoop some wort out using a small measuring cup and take my measurement. Most of the time there is visible suspended sediment in the sample.

The other day I was making a recipe that I have made enough times, I know what my numbers _should_ be at each point in the process. Because I got distracted though, I didn't check my pre-boil SG until about 20-30 min after I pulled the sample, and all the suspended sediment in the measuring cup had settled.

Embarrasingly enough, without sediment, the specimen read about 0.08 higher <g>. When I checked with a hydrometer (after correcting for temperature), the _higher_ reading seemed the correct one.

Was I supposed to be letting the sediment settle all along? Whoops. So I guess this recipe that I have been making for years has a higher ABV than I ever realized (since I always take my FG post-ferment readings with a hydrometer).

Anyone else here ever discover that the hard way?

 

[augiedoggy]

This was a question I had as well because the sediment does effect the readings. I make it a habit to get as clean a sample as I can to avoid this.

 

[kh54s10]

I have never done that and the couple of times I have checked, it agreed with my hydrometer. I guess it depends on how much sediment there is. I bag my hops so they don't add more, if that makes the difference.

 

[heckels]

I just ran into this today, actually. I was making a saison with honey added. Before my boil my OG with clear wort was 1.060. About 45 mins later I took a reading before adding the honey. This time there was a considerable amount of sediment in the sample and could only get a fuzzy 1.056, which of course should have closer to about 1.064 part way through my boil.

Note to self: "Grab a sample and let it settle before measuring."

 

[h22lude]

I don't think sediment affects the reading. Don't quote me on this but I think the refraction is based on soluble solids dissolved in the liquid. Sediment isn't a soluble dissolved solid.

 

[day_trippr]

I do a chocolate stout with low fat cocoa powder added at flame-out and a hydro reading is always 10 points higher than the math supports.
It's the one recipe I trust my refract more than the hydro...

Cheers!

 

[richl025]

I don't think sediment affects the reading. Don't quote me on this but I think the refraction is based on soluble solids dissolved in the liquid. Sediment isn't a soluble dissolved solid.

Well, I gotta say, my experience rather contradicts that.

 

[h22lude]

Well, I gotta say, my experience rather contradicts that.

There may be other things going on that made you think sediment affected your readings.

From the little research I did, sediment should not affect a hydrometer or refractometer reading. Only dissolved solids can affect it. In my 8 years of experience, I find this to be true. I've done beers with fruit it the mash to highly hopped NEIPAs and the refractometer reading are always spot on with my hydrometer readings which match what I expected.

 

[kh54s10]

The only thing I can think of would be very large particles in the wort that keep the liquid more toward a solid rather than a translucent. I don't think it should change the reading, just make it harder to see the scale.

As I said, my refractometer readings are accurate to the predicted and to hydrometer readings. So it is not my experience that sediment affects the reading.

 

[h22lude]

I agree. The sediment in a refractometer will make the line blurry but won't change the gravity.

Off topic, I tried to quote you using the app and every time I hit quote, this is the quote I got lol it isn't even a quote from you

i love me some bud light *****

 

[kh54s10]

I agree. The sediment in a refractometer will make the line blurry but won't change the gravity.

Off topic, I tried to quote you using the app and every time I hit quote, this is the quote I got lol it isn't even a quote from you

I had that the other day. I had selected a couple of things to quote, but didn't. Those stayed for a while. I think it may be a bug in the site.