Second AG batch second FG too high???

Guys, need some advice here... I've done two all grain batches, one was Yoppers Hoppy Amber Ale and one Milk Stout. I hit my mash temps and og's. Did starters, 1L and 1.8L respectively. Fermented both @ 67* for four weeks, but both FG's ended way high, amber ale @ 1.024 and milk stout @ 1.030. I used Denny fav on the amber ale and a Irish ale yeast on the stout. Any ideas? The stout is still in the primary, I've swirled it and put a heat rap on it in hopes of cranking up the the yeast again.

The 1.030 is high, but I wouldn't say way high for a milk stout. The 1.024 for the amber ale is too high, though.

If you've not had this problem previously, with extract batches, then the first place I would look is mash temperatures. Higher mash temperatures lead to more non-fermentables, which leads to high FG. Are you hitting your temperatures pretty closely? Is your thermometer accurate?

Are you using a hydrometer or refractometer for FG? If it's a refractometer, you need to use a correction program.

I use a digital probe thermometer, I also use a rubbermaid 10 gallon cooler for my mash tun. I can't get the probe down to the bottom of the grain bed, I suppose my temps could be higher deeper into the mash? My temps have been spot on, right at 154 and don't loose more than a degree or two over the 60 minute mash. I use both a hydrometer and a refractometer for the preboill and og readings. Only use my hydrometer for the fg. It seems like my mash temps might be too high based on my research, but 152 to 154 seem to be in the normal range. Looking back at my notes I was between 154 & 156 for the amber ale and 151 for the stout. Both hit right at 70% efficiency.

Yesterday I bottled a batch of Porter (essentially Palmer's Port o' Palmer recipe). It started with a very active primary fermentation (1 week), then racked to secondary for 3 weeks at 64i. OG of 1.053. FG is the issue. Initially measured at 1.023...which is higher than I expected. I covered and shook the tester and a surprising amount of pressure and head developed (as in overflowing...similar to wine before degassing...but better head retention!). Anyhow, since my friend was over to help decide how much cold brewed coffee to add, we needed the sample to blend with varying concentrations so I just ignored the reading. But it's bugged me ever since. My questions:
1) Could the high carbonation have "floated" the hydrometer? I believe so)
2) Is this a "relax" situation or should I be concerned I'm doing someting wrong? (I am quite sure I nailed my mash and sparge temps)
3) Once the beer is carbed and bottling sugar is converted, could I open a bottle, let it go completely flat and get a reasonably valid FG from that? (I've tried to search that one in the forums and come up empty...but I lose patience sometimes!)

Good technique is to degas a hydrometer sample, which can be a pain. For wine acid testing I nuke my sample in the microwave until it just starts to boil, then cool it for a reading.

You can also use a stir plate to degas a sample.

I have switched to a refractometer and no longer use the hydrometer. Sample size of a few drops, automatic temperature conpensation and no degassing required. One entry in a spreadsheet and I'm done, plus the spreadsheet becomes my fermentation notes.