Stuck with High SG

Hi!

First, thanks for the great resource, I've been creeping your forums for a while, ever since I started homebrewing. First time I've needed to post though.

We brewed a Belgian wit ale about 5 weeks ago using a partial mash recipe. The OG was pretty good at 1.053 (recipe estimated 1.048). For the first week or so it was fermenting like crazy, clogging airlock after airlock. After 2 weeks the fermentation died down a bit and during the third week, I tested the gravity 3 times with a day or two in between and found that the gravity stopped changing, but it was considerably higher than I expected: 1.022 (recipe estimated 1.010).

Since it was unchanged for so long, like I usually do, I racked it to secondary.

Then I thought that this seemed pretty high -- so I ran the numbers. I only got an apparent attenuation of only 58.5% when the yeast is expected to 74-78% (White Labs Belgian Wit 400). So I wasn't sure what was up.

I started reading about the yeast I saw that people have found it temperamental and needed to give it a swirl every once in a while. Well I didn't do this (thats what I get for reading after the fact).

Anyway I figured there would be more sugars to breakdown, so at the advice of the HBS I ordered this from, I pitched Nottingham and some pitchable yeast nutrient.

48 hours later no observable fermentation.

So here's what I think went wrong: This was the first time I used a propane burner (my new apartment has convection burners ) and I'm fairly certain I overheated the mash which resulted in a lot of unfermentable sugars in the wort. At least thats what I've come up with after reading through a number of posts here. The brew pot I used was deeper than the one I've traditionally used so I used a crappy comes-in-the-box thermometer instead of my usual one. I think the unfermentables probably account for the higher OG and the higher SG I currently have.

So my questions are this:
1. Does this sound right? My guess as to what went wrong?
2. I currently have amylase enzyme scheduled to be delivered tomorrow, should I throw this in there in attempt to lower the gravity? 1.022 seems really high to me.
3. Any other tips / suggestions?

Thanks again for the great resource, and thanks in advance.

How high did you overheat the mash? What were you targeting and what did you mash at?

Most Belgian yeast like to ferment slightly warm and are usually high flocculators as well. In addition to the high mash temps you may have fermented too cold? The yeast perhaps dropped out before full attenuation? Just another idea............

I am usually not one to try and mess with beers in this situation, I usually try to learn from what may have occurred so I don't repeat the same issues. I am usually always satisfied with the end result, it just may be slightly off. Sometimes messing around with things late in the process can screw things up more than they already are

AnthonyC said:

How high did you overheat the mash? What were you targeting and what did you mash at?

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The recipe said "approx. 155" and I stopped the burner when the thermometer neared 155. But its hard to say exactly since I'm not sure I can trust my thermometer.

Most likely the temp continued to rise a bit so you probably mashed high even at 155 and got a less fermentable wort. 150-152 is more desirable.

Be sure to calibrate your thermometer and watch your mash temps. I also asked about your yeast before, what strain and where did you ferment at?

Here's the datasheet on the yeast I used: http://www.whitelabs.com/beer/strains_wlp400.html

I ferment in a 6.5 better bottle thats kept in the closet in my spare bathroom. Its in the middle of the apartment so I'd guess the temperature stayed very close to the 72-77 range we try to keep the apartment at. It probably didn't get hotter than 77 and I don't think it would have gotten cooler than 72.

I replied yesterday but I think the message got caught up in the moderation queue because I'm a new poster and I posted a link. The yeast was White Labs Belgian Wit 400. The datasheet is on their website (that was the link that I think I got moderated for).

The fermenter was in a dark closet, the temperature no less than 72 and no higher than 78.

jheiv said:

I replied yesterday but I think the message got caught up in the moderation queue because I'm a new poster and I posted a link. The yeast was White Labs Belgian Wit 400. The datasheet is on their website (that was the link that I think I got moderated for).

The fermenter was in a dark closet, the temperature no less than 72 and no higher than 78.

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Your fermentation temps were definitely in range so I will go with the high mash temperatures giving you less fermentable wort resulting the high FG readings.

Be sure to get a quality thermometer and calibrate. In addition be sure you calibrate your hydrometer and correct for temperature.