Risks of pitching a high gravity starter?

Question

I just got a stir plate and was excited to make my first 1L starter with it. I googled the appropriate DME to water ratio and the first two results I found listed 1L to 1lb DME which seemed high but given the two sources I went with it.

After making the starter and pitching my yeast I started thinking about it more and realized this ratio much be off. It turned out that the instructions for the first source only called for a cup but listed a pound in the supplies. The second source was a typo which was corrected further down in the thread.

I decided that increasing the size of the starter was the best solution. I had a 1 gallon jug on hand and decided that adding another liter of tap water would be a decent compromise between having way too large a starter and having one that was the right gravity.

Ultimately, it seems like I'm dealing with a half-gallon batch of moderate-to-high gravity beer rather than a true starter. I should end up with way more yeast cells but I'm also going to stress the yeast more than I would have with an appropriate starter gravity. As such, should I be concerned about pitching this starter? If it's okay, would it make sense to split it off and keep a pint or so for a future batch or is the larger pitch rate just making up for the stressed yeast?

Answer 1

Just cold crash the starter, decant the beer off and pitch the yeast slurry.

The main function of a starter is to grow yeast to a proper cell count for your batch. It's actually pretty hard to over pitch and get bad results. The only negative to an over pitch is it will have less yeast ester profile in a beer, which can be bad if the style depends on those esters. Saison, wiesse, Belgian etc.

A secondary use and type of a starter is to pitch a proper cell count while it's at high krausen to reduce lag time. But this type of starter takes much more care so the starters beer doesn't introduce bad flavors. So it's temp needs to be controlled as you would in fermentation. Most importantly the starter wort should be very similar to the final beers. I've abandon this practice because to do it right takes a lot of time to prepare.

Answer 2

Assuming a 5 gallon batch, this over-sized starter will contribute roughly 10% of the volume of your beer. So any changes it makes to the flavor will likely be small and difficult to detect in even the most extreme cases. I wouldn't worry about it, I expect that you can probably pitch the starter without issue. That being said, let's consider a couple concerns.

What was the OG of the original recipe? If it was high, then you're better off having a large starter. For high gravity beers it is generally recommended to use starters on the larger side. If it was low, then your starter may contribute noticeably more sugar.

Is the DME you used similar to the grain or extract you used in the recipe? If so, then you're fine. If the DME is a nice neutral base, or is lighter than you're recipe, then you're fine. However, if you for some reason made a starter with a dark DME to get your hefeweizen going you might have a problem.

I wouldn't bother trying to save any of it, unless I was planning on brewing again very soon. That's more about my space than any particular concerns for the health or viability of saving a split of the starter.