I am not sure why all the worry about grape juice or whatever. THat stuff is mild compared to the acidic environment in the stomach. Some of the early studies on creatine used juices with no problems.
As far as dosing is concerned, Dr. Paul Greenhaff, who did most of the early research on creatine had it worked out in the mid 90s... excerpt below from: http://www.ajcn.org/cgi/content/full/72/2/607S
Bottom line, consume 5 grams 4 X day with some carbohydrates. THis loading period should last 5-6 days at most. Then creatine levels can be maintained with 2 grams per day (probably less). If you cease creatine supplementation after loading, it takes about 20 days for creatine levels to return to baseline....
"Total creatine concentrations in human skeletal muscle before and after creatine supplementation are shown in Figure 7 (48). The data show that 1 mo after supplementation with 20 g/d for 6 d, the total creatine concentration is not significantly different from the presupplementation value. It is also evident from this study that consumption of a small maintenance dose of 2 g/d after the initial loading phase will maintain a high total creatine concentration in the muscle for a period of 28 d. The efficacy of the maintenance dose in sustaining muscle creatine concentration beyond this period is unknown. The preceding discussion shows several times that the greatest increases in phosphocreatine availability and the largest improvements in performance appear to be found in persons with the largest increases in muscle creatine concentration. This suggests that an ergogenic effect of creatine ingestion on metabolism and performance during exercise and recovery may critically depend on the extent of muscle creatine uptake during ingestion. It also points to the importance of maximizing tissue creatine uptake when attempting to increase exercise performance via creatine ingestion. However, these findings do not constitute a license for the indiscriminate use of creatine. First, most muscle creatine uptake takes place during the initial days of creatine supplementation. In a study in which subjects consumed 30 g/d for 4 d, 30% of the total intake was retained during the initial 2 d of supplementation, compared with 15% from days 2–4 (32). There is no evidence that increasing intake above 20–30 g/d for 5–6 d has any potentiating effect on muscle creatine uptake (32, 48). In fact, a consistent finding from several studies is that there appears to be a definable upper limit to the intramuscular total creatine concentration of 160 mmol/kg dry mass (32, 39); once this limit is reached, further supplementation will simply result in excretion of creatine in the urine.
Another point to consider is that several factors identified as governing the extent of creatine uptake are largely independent of the amount consumed. One is the muscle total creatine concentration before supplementation; in general, the lower the initial total creatine concentration, the greater the extent of muscle creatine uptake (32, 39, 41). This precept is clearly illustrated in Figure 8 from work by Harris et al (32), and it is worth noting that even the lowest presupplementation values here fall well within the normal range. In individuals in whom the initial total creatine concentration is already relatively high, neither an appreciable uptake of creatine nor an effect on phosphocreatine resynthesis or performance has been found after creatine supplementation (39, 41). Thus, creatine supplementation can be considered to optimize the store of available high-energy phosphates in those individuals whose total creatine concentration lies at the lower end of the normal range, in the same manner as carbohydrate loading optimizes the muscle glycogen stores. Several means of promoting creatine uptake that 1) allow more individuals to approach the apparent upper limit to the muscle total creatine concentration and 2) do not involve increasing the creatine load have now been identified. One approach, described by Harris et al (32), is to combine creatine supplementation with exercise (Figure 9). In this study, 5 subjects receiving creatine supplementation performed 1 h of continuous, submaximal cycling exercise on each day of supplementation. Subjects conducted the exercise using one leg; the contralateral leg served as a control. As with creatine supplementation alone, a large interindividual variation occurred in response to the combination of creatine and exercise. However, the mean total creatine concentration of the muscle increased by 37% (the equivalent of 44 mmol/kg dry mass) when creatine was combined with exercise, as opposed to 26% (30 mmol/kg dry mass) with creatine supplementation alone. A second approach is to combine creatine ingestion with carbohydrate, a regimen that has a large potentiating effect on creatine uptake (49). This approach also reduces the amount of variation habitually seen in the extent of creatine uptake after creatine supplementation alone or in combination with exercise. In one study (57), 3 groups consumed 20 g creatine/d for 3 d (Figure 10). One of these groups consumed four 5-g doses of creatine dissolved in 250 mL of a warm, sugar-free, diluted orange drink. A second group followed each 5-g creatine load with 500 mL of a commercially available 18.5% simple carbohydrate solution (Lucozade; SmithKline Beecham, London, United Kingdom). A third group consumed creatine and simple carbohydrate in the same manner, with the addition of 1 h of cycling at 70% of maximal oxygen uptake on the morning of each day of supplementation immediately before creatine ingestion. A fourth group acted as a control and consumed only the sugar-free orange drink. Energy and macronutrient intakes were controlled throughout the study in all groups. Serum insulin was significantly elevated after carbohydrate ingestion when compared with creatine or placebo ingestion. Whole-body creatine retention was significantly increased when ingested in combination with the carbohydrate solution, probably because of a stimulatory effect of insulin. As shown in Figure 10, exercise did not add to creatine retention. Thus, combining creatine supplementation with carbohydrate ingestion appears to obviate the need for exercise during the supplementation period.